1. 性取向：自然存在的人类多样性
性取向可以被定义为个体对特定性别的持久情感、浪漫和/或性吸引。这种吸引是深刻且内在的，构成了个体身份认同的一个核心方面。性取向并非一个简单的二元选择，即并非仅仅是异性恋或同性恋，而是一个连续谱，涵盖了异性恋（对异性产生吸引）、同性恋（对同性产生吸引）、双性恋（对男性和女性都产生吸引）以及其他多元类型，如泛性恋、无性恋等 1。理解性取向的多样性，首先要认识到它是一个复杂的、多维度的现象，而非简单的行为偏好或生活方式选择。
从全球范围来看，人群中性取向的这种多样性是普遍存在的。尽管具体的统计数据可能因文化背景、调查方法和样本群体的差异而有所浮动，但有研究指出，非异性恋人群（包括同性恋、双性恋等）是社会中普遍存在的少数群体，其比例虽有差异，但始终是人类多样性的一部分。例如，一些研究将性取向视为多样性因素之一，而非异性恋者属于“未被充分代表的少数群体”（underrepresented minority, URM）范畴 23。另有研究探讨了同性恋人群中出现双性恋特征的现象 4。这些数据有力地表明，性取向的多样性是人类群体的一种自然特征，不应被视为“异常”或“疾病”。相反，科学界和主要的医学与心理学组织普遍认同性取向的多元性是人类固有的变异之一，与健康或适应性障碍无关。将非异性恋性取向病理化或试图“改变”的尝试（即所谓的“扭转治疗”），已被证明是无效且有害的，并遭到全球众多专业机构的谴责 56。这种科学共识强调了对所有性取向个体给予理解、尊重和支持的重要性，以促进一个更具包容性的社会环境 78910。
2. 基因的作用：从双生子研究到全基因组分析
2.1 双生子研究证据
为了探究性取向中遗传因素的贡献，双生子研究被广泛应用。这类研究通过比较同卵双胞胎（共享100%基因）和异卵双胞胎（平均共享50%基因）在特定性状上的一致性，来评估基因和环境因素的相对影响。如果同卵双胞胎在性取向方面的一致率显著高于异卵双胞胎，则表明遗传因素在其中发挥了作用。
多项研究结果一致显示，同卵双胞胎在性取向方面表现出更高的一致率。例如，有研究指出，同卵双胞胎在性取向方面的一致率高于异卵双胞胎1112。具体来说，当一个同卵双胞胎是同性恋时，其同胞也有更高的可能性是同性恋；而异卵双胞胎的这种一致性则较低。另一项研究也证实，性取向具有遗传成分，家族、双生子和领养研究表明，同性恋在家族中具有聚集性，同卵双胞胎的一致率高于异卵双胞胎，这与基因至少解释了性取向一半变异的假说相符 13。
然而，尽管同卵双胞胎的一致率显著高于异卵双胞胎，但它并非100% 14。这意味着即使是基因完全相同的个体，其性取向也可能存在差异，这强烈提示性取向的形成并非完全由基因决定。非共享环境因素（即同卵双胞胎个体之间独特的经历和环境）在性取向的发展中同样扮演着重要角色 14。例如，一项针对性取向不一致的同卵双胞胎进行的性唤起模式研究发现，尽管基因相同，但他们的性唤起模式却与各自自我报告的性取向一致，这进一步支持了非共享环境因素的重要性 14。
综合来看，双生子研究为性取向的遗传基础提供了有力证据，表明基因在塑造个体性取向倾向方面发挥了显著作用。然而，这些研究也明确指出，遗传因素并非唯一的决定性因素，环境因素，特别是那些在个体间存在差异的非共享环境因素，同样对性取向的最终形成至关重要。
2.2 GWAS研究突破
随着基因组测序技术的发展，全基因组关联研究（GWAS）为识别与复杂性状相关的特定基因位点提供了强大的工具。在性取向研究领域，GWAS的突破性进展进一步深化了我们对性取向遗传基础的理解。
2019年，一项里程碑式的大规模GWAS研究对超过47万名个体的同性性行为进行了分析，识别出5个与同性性行为显著相关的基因位点15。这些位点涉及的生物学通路具有潜在的生理学意义：
- 部分位点涉及嗅觉相关基因：例如，一个位点位于包含嗅觉受体基因簇的区域。嗅觉在动物的性吸引和配偶选择中扮演着重要角色，在人类中也可能通过影响感知和吸引力，间接影响性取向15。
- 部分位点涉及性激素调节通路：例如，一个位点与性激素调控有关，提示性激素在性取向发展中的潜在作用15。性激素，特别是睾酮和雌激素，在胎儿发育和青春期对大脑的组织化作用被认为是影响性行为和性取向的关键生物学因素。
- 其他位点：还包括与毛发脱落模式相关的位点（暗示可能与性激素水平或敏感性有关），以及其他一些功能尚待明确的区域15。
值得注意的是，尽管这些GWAS研究识别出了与同性性行为相关的基因位点，但研究人员强调，这些单个基因位点对性取向的解释力非常有限1516。具体而言，所有被检测的遗传变异总共仅能解释同性性行为变异的8%至25%，且这种遗传贡献在男性和女性之间存在部分重叠15。这意味着，没有任何一个“同性恋基因”可以单独决定个体的性取向。
进一步的研究，包括对汉族人群的GWAS研究，也发现了与男性性取向相关的基因位点，例如位于Xq27.3的_FMR1NB_和位于19q12的_ZNF536_基因17。这些研究进一步支持了性取向的遗传复杂性，并提示不同族裔人群中可能存在特异性的遗传影响。此外，一项针对男性性取向的GWAS研究也发现了染色体13上的_SLITRK6_（一个神经发育基因，主要在间脑表达）和染色体14上的_TSHR_基因附近的位点与性取向相关18。间脑包含的区域此前被报道在男性中根据性取向的不同而大小有差异，而_TSHR_基因的遗传变异可能有助于解释过去关于家族性甲状腺功能异常与男性同性恋之间的发现18。
这些GWAS研究共同揭示了性取向的遗传基础是高度复杂且多基因性的，涉及多个基因的微小效应累积，而非由单一基因决定1516。因此，仅凭这些基因位点，目前无法对个体的性取向进行有意义的预测15。这一发现对理解性取向的生物学基础至关重要，同时也提醒我们，基因并非唯一的决定因素，更不能将其简化为简单的遗传“开关”。
3. 非基因因素：子宫环境、激素与神经发育
3.1 孕期激素的潜在影响
除了基因，生命早期，特别是子宫内的环境，对性取向的形成也可能发挥着关键作用。其中，孕期激素暴露被认为是影响胎儿大脑性分化的一个重要因素，进而可能对未来的性取向产生潜在影响 1920。
睾酮等雄激素在胎儿发育过程中扮演着核心角色。研究认为，胎儿大脑的性分化（即向男性或女性方向发展）是由孕期雄激素水平决定的。如果在怀孕中后期，胎儿大脑经历一个睾酮激增期，大脑就会向男性方向发展；如果缺乏这一睾酮激增，大脑则倾向于女性化发展 1920。这种大脑性分化与生殖器官的性分化发生在不同的孕期阶段，因此这两个过程可以独立地受到影响 1920。
“手指长度比”（2D:4D ratio），即食指（第二指）与无名指（第四指）长度的比例，被广泛用作产前雄激素暴露的一个非侵入性指标 2122。通常认为，较低的2D:4D比值（即无名指相对于食指更长）与较高的产前雄激素暴露相关，这通常在男性中更为常见 2123。多项研究试图探索2D:4D比值与性取向之间的关联，以支持产前雄激素影响性取向的假说。例如，有荟萃分析表明，平均而言，女同性恋者的2D:4D比值可能低于异性恋女性（即更男性化），这提示女同性恋者在产前可能暴露于更高水平的雄激素 23。然而，并非所有研究都得出一致结论，也有研究发现女同性恋女性的2D:4D比值并未呈现出更男性化的趋势，且其与自我报告的男性化特征无关 24。这些差异可能与研究设计、样本量以及产前雄激素暴露测量的复杂性有关。
孕期激素，如雄激素，可能通过调节神经回路来影响性取向倾向。例如，动物模型研究显示，产前雄激素水平的实验性操纵可以影响成年后的身体形态，包括手指长度以及其他性状 22。在人类中，孕期母体雄激素水平与胎儿大脑发育的关联，可能通过影响大脑特定区域（如下丘脑）的结构和功能，进而对性取向产生影响 1920。下丘脑被认为是性取向和性别认同的关键神经回路所在区域 20。
此外，母体的压力水平、酒精和烟草消费以及一生中的应激源也可能与子代的产前雄激素负荷（通过2D:4D比值反映）呈正相关 25。这提示了母体环境因素可能通过影响激素水平，间接影响胎儿发育和未来的行为倾向。
需要强调的是，尽管存在这些关联性研究，但孕期激素对性取向的因果关系尚未完全明确。产前激素环境的复杂性、个体差异以及其他多重因素（如遗传、表观遗传、免疫反应等）的共同作用，使得这一领域的解释仍然处于探索阶段 1926。目前的研究主要表明，孕期激素暴露可能影响个体大脑的某些特定偏向，为性取向的形成提供了一种潜在的生物学基础，但并非单一或完全的决定因素。
3.2 神经结构的差异
性取向的神经生物学基础是当前神经科学研究的热点之一。多项研究致力于探究同性恋和异性恋个体在大脑结构和功能上的差异，特别关注下丘脑等被认为与性行为和性激素调节密切相关的脑区 19。
早期的里程碑式研究之一发现，异性恋男性下丘脑的第三间质核（INAH3）体积是女性的两倍多，而同性恋男性的INAH3体积与女性相似，约为异性恋男性的一半 27。这一发现提示了性取向可能与大脑特定核团的形态学差异有关，并暗示性取向具有生物学基础 2027。后续研究也继续支持下丘脑在性别认同和性取向中的关键作用，指出是脑结构的大小、神经元数量、分子组成、功能和连接性决定了我们的性别认同或性取向 19。例如，在同性恋男性中，室上核（suprachiasmatic nucleus，SCN）被观察到比异性恋男性更大 28。
更广泛的神经影像学研究也试图识别与性取向相关的脑区差异。一些研究指出，同性恋个体的大脑结构或连接模式可能更接近其非生理性别（sex-reversed）的异性恋者。例如，有研究发现，同性恋男性的部分皮层厚度与异性恋女性相似，而同性恋女性的这些指标则与异性恋男性相似 29。然而，这些发现并非普遍一致，也有研究发现，同性恋群体的部分脑区可能表现出“性别逆转”的特征，但同时也会展现出其独特的神经表型，而非简单地向另一性别的异性恋者靠拢 30。例如，一项研究发现同性恋个体白质束的性分化程度较低，自指网络的脑功能连接也较弱 29。另有研究发现，同性恋男性在某些脑区（如内侧前额叶和楔前叶）的皮层厚度比其他组更厚，而同性恋女性则没有显示出与异性恋女性的显著差异 29。
尽管这些研究揭示了性取向与大脑结构和功能之间可能存在的关联，但需要强调的是，这些发现大多是相关性而非因果性。目前的科学尚无法确定这些神经结构差异是性取向产生的原因，还是其发展过程中伴随的现象。此外，研究样本量小、研究方法多样性以及性别和性取向分类的复杂性等因素，都使得对这些神经生物学发现的解释需持谨慎态度 30。未来，结合更精细的神经影像技术、多模态数据分析以及纵向研究，有望更深入地阐明性取向的神经生物学基础。
3.3 环境因素的边界
在探讨性取向的形成时，环境因素常被提及。然而，需要明确的是，社会、家庭和文化环境通常不被认为是性取向本身的决定性因素，而是可能影响个体如何认知、表达以及应对其性取向。这些外部因素主要作用于个体性取向的“出柜”过程、社会认同以及心理健康状况，而非从根本上改变其性吸引的内在模式。
一个敌对或不接纳的家庭环境，例如存在虐待、家庭冲突或兄弟姐妹间的攻击行为，可能会对青少年的心理健康产生负面影响，并可能进一步影响他们对性取向的自我接纳和表达 31。虽然这些经历与性取向的直接形成没有因果关系，但它们可能加剧LGBTQ+（女同性恋、男同性恋、双性恋、跨性别者和酷儿）个体所面临的压力，特别是与歧视和边缘化相关的少数群体压力。
社会歧视、偏见和边缘化是LGBTQ+群体面临的特定压力源，这些社会决定因素显著影响他们的心理健康 32。研究表明，LGBTQ+个体面临更高的焦虑、抑郁和自杀风险 32。例如，一项研究发现，性少数青少年与异性恋同龄人相比，自杀未遂和自残的风险增加了约50%，即使在调整了遗传和共享环境因素以及儿童期精神病理学症状后，这种关联依然存在 33。这表明，与性少数身份相关的特定环境因素很可能增加了他们的心理健康风险。跨性别青少年尤其面临独特的挑战，包括高比例的性别烦躁和歧视导致的心理困扰 34。这些心理健康差异并非性取向本身导致的“病态”，而是社会不接纳、污名化和歧视的直接后果。
社会对LGBTQ+群体的接受度、反歧视法律以及医疗保健政策等支持性框架，有助于塑造社会接纳度和个体福祉 32。例如，学校环境在很大程度上影响LGBTQ+青少年的心理健康。支持性的学校干预措施，如积极的视觉展示、提供LGBTQ+支持团体、教师培训和包容性政策，被发现有助于减少LGBTQ+学生的心理健康问题 35。这表明，尽管环境不能改变性取向，但一个支持性和包容性的环境对于LGBTQ+个体的健康发展至关重要。
此外，文化和历史背景也塑造了性取向的社会建构和个人体验。例如，不同文化中对同性关系的态度和对女性之间情感联系的理解，可能会影响个体对自身性取向的认知和公开程度 36。
总而言之，社会、家庭和文化环境并不决定一个人的性取向是异性恋、同性恋还是双性恋。性取向的本质形成被认为更多地与生物学因素（基因、孕期激素、神经发育）相关。然而，这些环境因素确实在很大程度上影响了性少数群体个体的生活质量、心理健康，以及他们如何理解、表达和体验自己的性取向。
4. 科学共识与常见误区澄清
4.1 误区一“性取向是选择”
关于性取向的形成，最常见的误解之一便是认为性取向是一种个人选择，可以根据意愿进行改变。然而，主流科学研究和临床实践均已明确指出，性取向并非可以自主选择，也不是可以通过“改变”或“治疗”来扭转的行为模式。
性取向通常在个体青少年时期甚至更早的阶段逐渐形成并趋于稳定。青少年时期是个人身份认同形成的关键阶段，其中包括对性别和性身份的理解与发展37。纵向研究表明，性取向在青少年阶段具有相当的稳定性，这意味着个体对特定性别的持久吸引力并非是短暂的或可随意改变的。理解和接受自己的性取向是青少年身份认同发展中的一个重要组成部分38。试图改变性取向的做法，例如所谓的“扭转治疗”或“转化治疗”，已经被科学界和专业医学组织（包括美国精神病学协会、美国心理学协会等）认定为无效且具有潜在危害。这些干预措施不仅未能成功改变个体的性取向，反而可能导致严重的心理创伤，例如焦虑、抑郁、自杀风险增加，以及自我认同的瓦解。性少数群体面临更高的焦虑、抑郁和自杀风险，这在很大程度上与社会污名化和歧视，以及被强制进行扭转治疗等负面经历有关39。
此外，大量研究和临床观察一致表明，性取向是一种深植于个体内部的持久模式，它不是通过学习、模仿或个人意志所能轻易控制的。即使在面对巨大的社会压力、歧视和排斥时，性少数群体依然无法改变他们的性取向，这进一步证明了性取向的非选择性。例如，有研究指出，对女同性恋、男同性恋、双性恋和跨性别（LGBT）人群的戒烟干预措施的系统性回顾强调了针对该特定群体的健康服务需求，也从侧面印证了性取向作为一种稳定的人群分类而非可变选择的内在属性40。
因此，科学共识明确否定了“性取向是选择”的观点。性取向是人类多样性的一部分，其形成涉及复杂的生物学和发展过程，而非个人意愿的产物。
4.2 误区二“基因决定一切”
另一个普遍存在的误解是认为“基因决定一切”，即一旦发现性取向的遗传成分，就意味着性取向完全由基因编码，个体无法改变。然而，这种观点过于简化了生命科学的复杂性，忽略了基因与环境之间深刻而动态的交互作用。正如前文所述，尽管双生子研究和GWAS研究均证实了性取向具有遗传基础，但遗传因素的解释力远未达到100% 4142。
事实上，现代科学对性取向的理解是一个多维度、多层次的复杂过程，涉及遗传、生物发育和环境等多种因素的动态交互。
- 基因并非独立作用：基因通过影响大脑结构、神经递质系统以及激素敏感性等生物学过程来发挥作用 2043。例如，GWAS研究发现的基因位点可能与嗅觉受体或激素调节有关，这些基因本身并不直接“编码”性取向，而是通过调节生物通路，为某种性取向倾向提供生物学 predispositions。
- 生物发育的关键作用：孕期激素环境被认为是性取向形成的重要非遗传生物学因素。胎儿在子宫内暴露于不同水平的性激素，会影响大脑的性分化，从而可能影响个体的性取向倾向 2044。这种激素作用本身也是基因与环境（子宫内的生化环境）交互的结果。例如，性激素对神经发育的影响与基因的表达模式相关，尤其是在关键的发育时期 45。
- 环境的复杂性与非决定性：虽然社会环境（如家庭教养、社会文化影响）不被认为是性取向的决定性因素，但它无疑会塑造个体对自身性取向的认知、表达和体验。社会接纳度、歧视水平和支持系统等外部因素，对LGBTQ+个体的心理健康和福祉产生深远影响 46。这些环境因素并非直接“创造”性取向，而是与个体的生物学 predispositions相互作用，影响性取向的发展轨迹和公开程度。
因此，将性取向归结为单一的基因决定论是一种过时的、不准确的观点。科学界普遍的共识是，性取向是由遗传、产前生物学发育（如激素暴露、神经结构形成）以及后天个体经验（非共享环境）等多种因素复杂交互作用的结果 44。目前，没有任何单一的理论或模型能够完全解释性取向的形成机制，这反映了人类性状的内在复杂性。这一理解促使我们超越简单的“先天或后天”的二元对立思维，认识到生命现象的丰富性和多变性。
4.3 科学共识总结
综合上述讨论，科学界在性取向的形成机制上已达成一个重要的共识：性取向是多维度因素动态交互作用的结果，而非由单一因素（无论是基因、激素还是环境）独立决定。目前没有任何一种单一理论能够完全解释所有个体性取向的形成机制。
这一共识的要点包括：
- 遗传因素扮演重要角色，但并非完全决定性：双生子研究明确指出遗传对性取向具有显著影响，同卵双胞胎的一致性高于异卵双胞胎 47。然而，即使是基因完全相同的同卵双胞胎，其性取向也可能不同，这表明基因并非唯一的决定因素。GWAS研究进一步识别出与同性性行为相关的基因位点，但这些位点仅能解释性取向变异的一小部分（例如，不到1%的个体差异），且多个基因的微小效应共同作用，强调了其多基因、复杂遗传的特性 26。因此，不存在单一的“同性恋基因”。
- 生物发育（特别是产前环境）是关键影响因素：子宫内的激素环境，尤其是产前雄激素水平，被认为是影响胎儿大脑性分化，进而塑造性取向倾向的重要生物学因素 4447。例如，“手指长度比”（2D:4D ratio）作为产前雄激素暴露的指标，与性取向之间存在一些关联性研究 26。此外，大脑的神经结构差异，当下丘脑等脑区在同性恋和异性恋个体中呈现出的结构或连接模式差异，也为性取向的生物学基础提供了线索 48。
- 环境因素影响性取向的表达和体验，而非其根本形成：社会、文化、家庭等外部环境因素，不会“决定”个体的性取向。然而，它们对个体如何认知、接受、表达和体验其性取向具有深远影响 49。一个充满歧视和不接纳的环境可能导致性少数群体面临更高的心理健康风险，如焦虑、抑郁和物质滥用 505152；而一个支持和包容的环境则有助于促进其福祉 51。这些环境因素更多地影响了个体的社会适应和心理状态，而非性吸引的内在模式本身。
因此，性取向的形成是一个复杂的生物-心理-社会过程。它既不是完全的“先天”宿命，也非纯粹的“后天”选择。相反，它是遗传倾向、早期生物发育（特别是胎儿期大脑对激素的敏感性）与个体在其生命历程中独特的生物学和非共享环境因素之间动态而复杂的相互作用。未来的研究将继续探索这些因素是如何精细地相互作用，从而导致人类性取向的惊人多样性。
5. 理解性取向的意义：从科学到社会
对性取向形成机制的科学探索，其意义远不止于揭示生物学或心理学原理本身。它不仅具有深远的科学价值，对人类多样性和神经发育机制的理解做出贡献，更在社会层面发挥着关键作用，有助于减少歧视、推动包容性政策，并最终促进一个更加公正和健康的社会。
5.1 科学价值
深入研究性取向的生物学、心理学和社会学基础，极大地拓展了我们对人类复杂性的认知。
- 推动对人类生物多样性的认知：性取向研究揭示了人类在情感、浪漫和性吸引方面的自然多样性，挑战了传统上对“正常”和“异常”性行为的二元化认知。通过双生子研究、全基因组关联分析（GWAS）以及对产前激素和神经结构差异的探索，科学家们证实了性取向作为一种复杂的人类特质，其形成涉及多基因遗传、表观遗传以及早期生物发育等多种因素的复杂交互 53。这种多样性并非缺陷，而是人类物种内在变异的一部分，其研究有助于深化我们对生命复杂性的理解。
- 深化对神经发育机制的理解：性取向的神经生物学研究，特别是对下丘脑等脑区结构和功能的探究，为我们理解大脑如何塑造高级认知和情感过程提供了宝贵线索。例如，对下丘脑INAH3核团、室上核（SCN）以及皮层厚度等差异的研究，不仅可能揭示性取向的生物学基础，也为神经科学领域研究大脑如何编码个体身份、情绪和行为模式提供了新视角。这些发现有助于我们更好地理解大脑性分化和神经回路在行为倾向形成中的作用，对整个神经发育领域具有指导意义。
- 为相关疾病研究提供线索：虽然性取向本身并非疾病，但对性取向形成机制的理解，可以为一些与性别和性发育相关的临床病症提供新的研究思路。例如，对产前激素暴露和大脑发育的研究，可能有助于解释某些性别认同障碍（如性别烦躁）的生物学基础，从而为受影响个体提供更精准的干预策略。此外，性少数群体面临的健康差异，如更高的心理健康问题发生率 5455，促使研究人员探索这些差异背后的社会、心理及生物学机制，从而开发更有效的、针对性的医疗和心理支持方案 39。例如，少数群体压力模型（Minority Stress Model）解释了歧视和污名化如何导致性少数群体的心理健康问题，而科学研究能够为这些问题提供干预的理论基础 56。
5.2 社会影响
基于科学对性取向的认知，对于构建一个更加包容和公正的社会具有不可估量的社会影响。
- 减少歧视与反污名化教育：科学研究的发现有助于指出性取向不是一种选择，也不是可以“治愈”的疾病，而是自然存在的人类多样性的一部分。这一共识是反歧视教育和政策的基石。它有力地驳斥了对性少数群体的污名化和偏见，有助于消除不公正待遇。当社会普遍认识到性取向是根深蒂固且非个人选择的特质时，人们更有可能对性少数群体抱以理解和尊重，而不是指责和排斥。研究表明，公众对性取向多样性的接受程度与对学校中相关教育计划的支持度呈正相关，这能够促进对性少数群体的接纳，减少同性恋恐惧症和跨性别恐惧症的发生 57。
- 推动包容政策与平等权益保护：科学研究的结论为倡导性少数群体的平等权利和包容性政策提供了坚实的证据支持。例如，对性少数群体健康和社会护理需求的认识 58，以及在医疗实践中推行多样性、公平、包容和正义的努力 59，均有助于推动法律和政策的改革，例如反歧视法、婚姻平权、伴侣权益、医疗保障以及工作场所的平等机会等。这些政策的实施，不仅能改善性少数群体的生活质量，也能促进整个社会的公平与和谐。例如，针对性少数群体的健康不平等问题，科学研究支持制定专门的、文化敏感的医疗保健策略，以满足其独特需求，改善其健康状况 54。
- 强调性取向多样性是人类社会的正常组成：性取向研究有助于强调人类性取向的多元性和丰富性，将其视为人类社会正常且有价值的组成部分。这有助于改变公众观念，将性少数群体从边缘地位拉回到社会中心，使其能够充分参与社会生活，发挥个人潜能。一个真正包容的社会，是尊重并庆祝所有成员多样性的社会，包括性取向的多样性。例如，心理学领域对性与性别多样性研究的交叉性视角，以及儿童发展中对残疾歧视的社会认知偏见研究，都揭示了社会如何理解和应对多样性，并能促进对“差异”的尊重，培养更强的社会凝聚力和同理心 6061。
总之，对性取向的科学研究不仅深化了我们对自身和世界的认识，更重要的是，它为建设一个更加理解、尊重和包容多元化的社会提供了重要的科学基础和道德指南。
内容由 AI 生成，仅供参考，请仔细甄别
参考文献
1Bisexuality: the state of the union.PubMed
Paula C Rodríguez Rust
Annu Rev Sex Res. 2002;13:180-240.
In many contemporary Occidental societies, bisexuality is paradoxical. Commonly conceived as a combination of heterosexuality and homosexuality, bisexuality as such became conceivable only after the popularization of the hetero/homosexual dichotomy during the late 19th and 20th centuries. Paradoxically, however, the concepts of hetero- and homosexuality, reflecting the cultural belief that an individual's feelings of sexual attraction are naturally directed toward the other sex or, alternatively, toward the same sex, simultaneously renders bisexuality--as an attraction to both genders--inconceivable. In this article, I review the historical and cultural processes that produced the paradoxical conceivability of bisexuality. I then discuss the cultural attitudes toward bisexuality that result from this paradox and show how scientific research on bisexuality has been guided by popular conceptions of, and attitudes toward, bisexuality. Finally, I review efforts to reconceptualize bisexuality for both political and scientific purposes, and summarize recent research on bisexuality using these reconceptualizations. This summary includes research on the prevalence of bisexuality, prejudice against bisexuals, patterns of bisexual behavior, and the meaning of bisexual self-identity.
2Assessing the evolving definition of underrepresented minority and its application in academic medicine.PubMed
Kathleen Raquel Page, Laura Castillo-Page, Norma Poll-Hunter, et al.
Acad Med. 2013 Jan;88(1):67-72. doi: 10.1097/ACM.0b013e318276466c.
PURPOSE: To assess how U.S. academic health centers (AHCs) define the term underrepresented minority (URM) and apply it to their diversity programs, following the 2003 revision of the Association of American Medical Colleges' (AAMC's) definition of URM. METHOD: In 2010, the authors developed and deployed a cross-sectional survey of diversity leaders at 106 AHCs. The survey included questions about the diversity leader and institution's diversity program; institution's URM definition; application of that definition; and the diversity leader's perceptions of the representation and institutional contribution of various ethnic/racial groups. The authors used descriptive statistics to analyze the results. RESULTS: Of the 106 diversity leaders invited, 89 (84.0%) responded and 78 (73.6%) provided a working definition of URM. Most programs (40/78; 51%) used the 2003 AAMC definition of URM, which includes racial/ethnic groups that are underrepresented in medicine relative to local and national demographics. Only 14.1% (11/78) used the pre-2003 AAMC definition, which included only African Americans, Mexican Americans, Native Americans, and mainland Puerto Ricans. Approximately one-third (23/78; 29.5%) also considered other diversity factors, such as socioeconomic status, sexual orientation, and disability, in defining URM. Fifty-eight respondents (74.4%) confirmed that their diversity programs targeted specific groups. CONCLUSIONS: The definition of URM used by diversity programs at U.S. AHCs varied widely. Although some classified URMs by racial/ethnic categories, the majority defined URM more broadly to encompass other demographic and personal characteristics. This shift should prepare academic medicine to eliminate health disparities and meet the health needs of an increasingly diverse population.
3Clinical psychology students' perceptions of diversity training: a study of exposure and satisfaction.PubMed
Debbie Green, Tamora A Callands, Alison M Radcliffe, et al.
J Clin Psychol. 2009 Oct;65(10):1056-70. doi: 10.1002/jclp.20605.
This study examined clinical psychology graduate students' definitions of diversity and their perceptions of their exposure to and satisfaction regarding their level of diversity training. Four hundred and ninety-one students from Counsel of University Directors of Clinical Psychology (CUDCP) member programs completed an online survey. Overall, students perceived that their programs considered diversity narrowly, concentrating primarily on ethnicity, race, and culture to the neglect of sexual orientation, religion, language, and physical disability. Likewise, students expressed greater satisfaction with training regarding ethnicity/race and gender than broader areas of diversity, but rated the importance of addressing all areas of diversity as high. Although this study underscores the limited experience that students perceive they have had with various underrepresented groups, programs appear to have incorporated a variety of diversity training modalities that could be expanded upon to meet the interests of psychology students.
4Bisexual Phenomena Among Gay-Identified Men.PubMed
Theodore L Semon, Kevin J Hsu, A M Rosenthal, et al.
Arch Sex Behav. 2017 Jan;46(1):237-245. doi: 10.1007/s10508-016-0849-5. Epub 2016 Sep 15.
A high proportion of self-identified gay men exhibit aspects of bisexuality during their lives. Some identify as bisexual before later identifying as gay; this has been called transitional bisexuality. Although many gay men report no attraction to women-or even sexual disgust toward them-others report some slight attraction to women. The latter have been studied as mostly homosexual men. We studied men with and without a history of transitional bisexuality, as well as mostly homosexual (i.e., those with Kinsey scores of 5) and completely homosexual (i.e., those with Kinsey scores of 6) men with respect to their sexual history with women, their current self-reported sexual arousal and disgust toward women and men, and their patterns of genital sexual arousal to female and male stimuli. Gay men with a history of transitional bisexuality generally lacked current sexual attraction and sexual arousal to women, compared with other gay men. Thus, transitional bisexuality among future gay men is mostly a matter of transitional bisexual identification. In contrast, mostly homosexual men showed statistically significant increases in genital arousal to female stimuli, compared with completely homosexual men.
5The scope and nature of sexual orientation and gender identity and expression change efforts: a systematic review protocol.PubMed
David J Kinitz, Travis Salway, Elisabeth Dromer, et al.
Syst Rev. 2021 Jan 8;10(1):14. doi: 10.1186/s13643-020-01563-8.
BACKGROUND: Sexual orientation and gender identity and expression change efforts (SOGIECE) are a set of scientifically discredited practices that aim to deny and suppress the sexual orientations, gender identities, and/or gender expressions of sexual and gender minorities (SGM). SOGIECE are associated with significant adverse health and social outcomes. SOGIECE continue to be practiced around the world, despite denouncements from professional bodies and survivors, as well as calls for legislative advocacy to prohibit SOGIECE and protect SGM. There are substantial gaps in the availability of consolidated international research to support and refine legislative proposals related to SOGIECE, including those currently underway to enforce bans in Canada and elsewhere. We therefore propose the first systematic review of international data on SOGIECE that will outline the scope and nature of these practices worldwide. Specifically, we aim to estimate how many SGM have been exposed to SOGIECE, which sub-groups of SGM experience higher rates of SOGIECE, and how estimates of SOGIECE vary over time and place. In addition, we aim to describe when, where, how, and under what circumstances SGM are exposed to SOGIECE. METHODS: To locate an interdisciplinary swath of papers, nine (9) bibliographic databases will be searched: Medline (OVID), Embase (OVID), PsycInfo and Social Work Abstracts via EBSCO, CINAHL, Web of Science Core Collection, LGBTQ+ Source, and Proquest Dissertations & Theses Global and Sociology Collection (ProQuest). A gold standard search will be developed for Medline and adapted to the other databases. Grey literature will be searched at relevant websites, and reference harvesting will be performed in relevant SOGIECE scientific consensus statements. Two authors will independently screen abstracts/titles, screen full texts, abstract data, and apply risk of bias assessments. A narrative synthesis will be implemented to summarize findings. DISCUSSION: This review will address the gap in synthesized data regarding the prevalence of SOGIECE, social correlates of SOGIECE, variations of SOGIECE over time and place, and the circumstances, settings, and time-points of SOGIECE exposure. Findings from this review will directly inform ongoing and new legislative efforts to ban SOGIECE and other interventions that aim to stem SOGIECE practices and support SOGIECE survivors. SYSTEMATIC REVIEW REGISTRATION: Registration with PROSPERO can be found under the registration number: CRD42020196393 .
6Statement of the Independent Forensic Expert Group on Conversion Therapy.PubMed
Djordje Alempijevic, Rusudan Beriashvili, Jonathan Beynon, et al.
Torture. 2020;30(1):66-78. doi: 10.7146/torture.v30i1.119654.
Conversion therapy is a set of practices that aim to change or alter an individual's sexual orientation or gender identity. It is premised on a belief that an individual's sexual orientation or gender identity can be changed and that doing so is a desirable outcome for the individual, family, or community. Other terms used to describe this practice include sexual orientation change effort (SOCE), reparative therapy, reintegrative therapy, reorientation therapy, ex-gay therapy, and gay cure. Conversion therapy is practiced in every region of the world. We have identified sources confirming or indicating that conversion therapy is performed in over 60 countries. In those countries where it is performed, a wide and variable range of practices are believed to create change in an individual's sexual orientation or gender identity. Some examples of these include: talk therapy or psychotherapy (e.g., exploring life events to identify the cause); group therapy; medication (including anti-psychotics, anti- depressants, anti-anxiety, and psychoactive drugs, and hormone injections); Eye Movement Desensitization and Reprocessing (where an individual focuses on a traumatic memory while simultaneously experiencing bilateral stimulation); electroshock or electroconvulsive therapy (ECT) (where electrodes are attached to the head and electric current is passed between them to induce seizure); aversive treatments (including electric shock to the hands and/or genitals or nausea-inducing medication administered with presentation of homoerotic stimuli); exorcism or ritual cleansing (e.g., beating the individual with a broomstick while reading holy verses or burning the individual's head, back, and palms); force-feeding or food deprivation; forced nudity; behavioural conditioning (e.g., being forced to dress or walk in a particular way); isolation (sometimes for long periods of time, which may include solitary confinement or being kept from interacting with the outside world); verbal abuse; humiliation; hypnosis; hospital confinement; beatings; and "corrective" rape. Conversion therapy appears to be performed widely by health professionals, including medical doctors, psychiatrists, psychologists, sexologists, and therapists. It is also conducted by spiritual leaders, religious practitioners, traditional healers, and community or family members. Conversion therapy is undertaken both in contexts under state control, e.g., hospitals, schools, and juvenile detention facilities, as well as in private settings like homes, religious institutions, or youth camps and retreats. In some countries, conversion therapy is imposed by the order or instructions of public officials, judges, or the police. The practice is undertaken with both adults and minors who may be lesbian, gay, bisexual, trans, or gender diverse. Parents are also known to send their children back to their country of origin to receive it. The practice supports the belief that non-heterosexual orientations are deviations from the norm, reflecting a disease, disorder, or sin. The practitioner conveys the message that heterosexuality is the normal and healthy sexual orientation and gender identity. The purpose of this medico-legal statement is to provide legal experts, adjudicators, health care professionals, and policy makers, among others, with an understanding of: 1) the lack of medical and scientific validity of conversion therapy; 2) the likely physical and psychological consequences of undergoing conversion therapy; and 3) whether, based on these effects, conversion therapy constitutes cruel, inhuman, or degrading treatment or torture when individuals are subjected to it forcibly2 or without their consent. This medico-legal statement also addresses the responsibility of states in regulating this practice, the ethical implications of offering or performing it, and the role that health professionals and medical and mental health organisations should play with regards to this practice. Definitions of conversion therapy vary. Some include any attempt to change, suppress, or divert an individual's sexual orientation, gender identity, or gender expression. This medico-legal statement only addresses those practices that practitioners believe can effect a genuine change in an individual's sexual orientation or gender identity. Acts of physical and psychological violence or discrimination that aim solely to inflict pain and suffering or punish individuals due to their sexual orientation or gender identity, are not addressed, but are wholly condemned. This medico-legal statement follows along the lines of our previous publications on Anal Examinations in Cases of Alleged Homosexuality1 and on Forced Virginity Testing.2 In those statements, we opposed attempts to minimise the severity of physical and psychological pain and suffering caused by these examinations by qualifying them as medical in nature. There is no medical justification for inflicting on individuals torture or other cruel, inhuman, or degrading treatment or punishment. In addition, these statements reaffirmed that health professionals should take no role in attempting to control sexuality and knowingly or unknowingly supporting state-sponsored policing and punishing of individuals based on their sexual orientation or gender identity.
7Culturally Competent Gender, Sex, and Sexual Orientation Information Practices and Electronic Health Records: Rapid Review.PubMed
Kelly Davison, Roz Queen, Francis Lau, et al.
JMIR Med Inform. 2021 Feb 11;9(2):e25467. doi: 10.2196/25467.
BACKGROUND: Outdated gender, sex, and sexual orientation (GSSO) information practices in health care contribute to health inequities for sexual and gender minorities (SGMs). Governments, statistics agencies, and health care organizations are developing and implementing modernized practices that support health equity for SGMs. Extending our work, we conducted a rapid review of grey literature to explore information practices that support quality health care for SGMs. OBJECTIVE: The aim of this rapid review of grey literature was to elucidate modern GSSO information practices from leading agencies for adaptation, adoption, and application by health care providers and organizations seeking to modernize outdated GSSO information practices that contribute to health inequities among SGMs. METHODS: We searched MEDLINE and Google from 2015 to 2020 with terms related to gender, sex, sexual orientation, and electronic health/medical records for English-language grey literature resources including government and nongovernment organization publications, whitepapers, data standards, toolkits, health care organization and health quality practice and policy guides, conference proceedings, unpublished academic work, and statistical papers. Peer-reviewed journal articles were excluded, as were resources irrelevant to information practices. We also screened the reference sections of included articles for additional resources, and canvassed a working group of international topic experts for additional relevant resources. Duplicates were eliminated. ATLAS.ti was used to support analysis. Themes and codes were developed through an iterative process of writing and discussion with the research team. RESULTS: Twenty-six grey literature resources met the inclusion criteria. The overarching themes that emerged from the literature were the interrelated behaviors, attitudes, and policies that constitute SGM cultural competence as follows: shared language with unambiguous definitions of GSSO concepts; welcoming and inclusive care environments and affirming practices to reduce barriers to access; health care policy that supports competent health care; and adoption of modernized GSSO information practices and electronic health record design requirements that address invisibility in health data. CONCLUSIONS: Health equity for SGMs requires systemic change. Binary representation of sex and gender in electronic health records (EHRs) obfuscates natural and cultural diversity and, in the context of health care, places SGM patients at risk of clinical harm because it leads to clinical assumptions. Agencies and agents in health care need to be equipped with the knowledge and tools needed to cultivate modern attitudes, policies, and practices that enable health equity for SGMs. Adopting small but important changes in the language and terminology used in technical and social health care systems is essential for institutionalizing SGM competency. Modern GSSO information practices depend on and reinforce SGM competency in health care.
8Sexual prejudice.PubMed
Gregory M Herek, Kevin A McLemore
Annu Rev Psychol. 2013;64:309-33. doi: 10.1146/annurev-psych-113011-143826. Epub 2012 Sep 17.
Despite shifts toward greater acceptance in U.S. public opinion and policy, lesbian, gay, and bisexual people remain widely stigmatized. This article reviews empirical research on sexual prejudice, that is, heterosexuals' internalization of cultural stigma, manifested in the form of negative attitudes toward sexual minorities and same-sex desires and behaviors. After briefly reviewing measurement issues, we discuss linkages between sexual prejudice and religion, gender, sexuality, and related variables, and consider how the cultural institutions encompassing these domains create a social context within which individual expressions of prejudice can meet important psychological needs. These include needs for securing social acceptance, affirming values that are central to one's self-concept, and avoiding anxiety and other negative emotions associated with threats to self-esteem. We conclude by discussing factors that may motivate heterosexuals to reduce their own sexual prejudice, including intergroup contact, as well as avenues for future empirical inquiry.
9Essential Principles to Create an Equitable, Inclusive, and Diverse EMS Workforce and Work Environment: A Position Statement and Resource Document.PubMed
Sylvia Owusu-Ansah, Rickquel Tripp, Stacy N Weisberg, et al.
Prehosp Emerg Care. 2023;27(5):552-556. doi: 10.1080/10903127.2023.2187103. Epub 2023 Mar 24.
POSITION STATEMENTEmergency medical services (EMS), similar to all aspects of health care systems, can play a vital role in examining and reducing health disparities through educational, operational, and quality improvement interventions. Public health statistics and existing research highlight that patients of certain socioeconomic status, gender identity, sexual orientation, and race/ethnicity are disproportionately affected with respect to morbidity and mortality for acute medical conditions and multiple disease processes, leading to health disparities and inequities. With regard to care delivery by EMS, research demonstrates that the current attributes of EMS systems may further contribute to these inequities, such as documented health disparities existing in EMS patient care management, and access along with EMS workforce composition not being representative of the communities served influencing implicit bias. EMS clinicians need to understand the definitions, historical context, and circumstances surrounding health disparities, health care inequities, and social determinants of health in order to reduce health care disparities and promote care equity. This position statement focuses on systemic racism and health disparities in EMS patient care and systems by providing multifaceted next steps and priorities to address these disparities and workforce development. NAEMSP believes that EMS systems should:Adopt a multifactorial approach to workforce diversity implemented at all levels within EMS agencies.Hire more diverse workforce by intentionally recruiting from marginalized communitiesIncrease EMS career pathway and mentorship programs within underrepresented minorities (URM) communities and URM-predominant schools starting at a young age to promote EMS as an achievable profession.Examine policies that promote systemic racism and revise policies, procedures, and rules to promote a diverse, inclusive, and equitable environment.Involve EMS clinicians in community engagement and outreach activities to promote health literacy, trustworthiness, and education.Require EMS advisory boards whose composition reflects the communities they serve and regularly audit membership to ensure inclusion.Increase knowledge and self-awareness of implicit/unconscious bias and acts of microaggression through established educational and training programs (i.e., anti- racism, upstander, and allyship) such that individuals recognize and mitigate their own biases and can act as allies.Redesign structure, content, and classroom materials within EMS clinician training programs to enhance cultural sensitivity, humility, and competency and to meet career development, career planning, and mentoring needs, particularly of URM EMS clinicians and trainees.Discuss cultural views that affect health care and medical treatment and the effects of social determinants of health on care access and outcomes during all aspects of training.Design research and quality improvement initiatives related to health disparities in EMS that are focused on racial/ethnic and gender inequities and include URM community leaders as essential stakeholders involved in all stages of research development and implementation.
10Improving Sexual and Gender Minority Cancer Care: Patient and Caregiver Perspectives From a Multi-Methods Pilot Study.PubMed
Miria Kano, Shoshana Adler Jaffe, Stephanie Rieder, et al.
Front Oncol. 2022 May 6;12:833195. doi: 10.3389/fonc.2022.833195. eCollection 2022.
PURPOSE: Up to 1 million lesbian, gay, bisexual, and transgender (i.e., sexual and gender minority, SGM) individuals in the United States have histories of cancer. This medically underserved population is diverse, with complex sexualities and gender identities, and distinct health concerns. SGM persons experience disproportionate risks for, and rates of, anal, breast, cervical, colorectal, endometrial, lung, and prostate cancers, in addition to cancers affecting transgender persons who have undergone sex-reassignment. SGM individuals are linked by shared experiences of stigmatization as a minority population for which little cancer research has been conducted. SGM cancer patients frequently report reluctance to seek healthcare, have poorer outcomes following diagnosis, engage in elevated risk behaviors (i.e. smoking and alcohol use) even after cancer diagnosis, have difficulty making emotional adjustment to illness, and experience higher rates of psychological distress. They report less satisfaction with cancer care, deficiencies in patient-centeredness and shared decision-making, gaps in care, and social isolation. Minority stress resulting from experiences of anti-SGM sentiment and discrimination affects cancer patients and their informal cancer caregivers. Our paper presents findings from a pilot study to identify gaps and opportunities to improve cancer care for SGM patients and caregivers at the University of New Mexico Comprehensive Cancer Center. METHODS: Between June 2020 and July 2021, we used a multi-methods research design informed by ecological theory to collect qualitative and quantitative data regarding cancer patient and caregiver quality of life (QoL) and experiences of cancer and survivorship care. We used PROMIS measures distributed REDCap to assess QoL (i.e., fatigue, pain interference, pain intensity, anxiety, depression, emotional support, social isolation, and companionship), and conducted in-depth semi-structured interviews. We recruited 10 SGM cancer patients and 8 heterosexual, cisgender (H/C) patient matches, and their self-identified informal cancer caregivers (n=36, dyad total n=18). Interviews ranged from 1 to 2 hours, were audio-recorded and transcribed for analysis. The study was approved by the University of New Mexico Human Research Protections Office Institutional Review Board. RESULTS: Results of the PROMIS QoL assessments indicated that SGM patients reported greater anxiety [mean (SD) = 54.5 (8.8)] and depression [mean (SD) = 49.3 (4.8)] than H/C patients [mean (SD)=51.6 (7.5) and 45.4 (6.8) respectively], while heterosexual, cisgender (H/C) patients reported higher fatigue [mean (SD) =52.04 (8.18)] and stronger pain intensity than SGM patients [mean (SD)=48.3 (9.1) and 37.8 (9.1) respectively]. SGM patients reported higher levels of social isolation [mean (SD) = 48.3 (7.3) vs. 42.1 (7.4) for H/C patients, whereas H/C patients reported more emotional support (mean (SD) =57.5 (9.3) vs. 53.0 (6.9)] and companionship [mean (SD) = 55.2 (8.6) vs. 51.5 (11.0)]. SGM and H/C differences in caregiver QoL were most notable with regards to higher levels of fatigue [mean (SD) = 47.1 (6.0) for SGM, and 42.4 (11.5) for H/C] and companionship [mean (SD) = 55.3 (6.0) for SGM, and 50.9 (5.5) for H/C]. Qualitative interviews supported our quantitative results. SGM patients and caregivers articulated experiences of anti-SGM stigma and discrimination contributing to minority stress that influenced their initial cancer care encounters. SGM dyads had more trepidation and/or medical mistrust during initial cancer care encounters when compared to H/C patients and caregivers. SGM patients questioned care that was not culturally responsive to SGM preferences, while H/C patients were more apt to identify gaps in communication and perceived lack of clarity regarding cancer care delivery. Although SGM patients experienced high satisfaction with their cancer care once they developed trust with their providers, they discussed desires to have more direct conversations with their oncologists about their sexual orientation and gender identities and sexual health. All patients and providers in the study (SGM and H/C) appreciated their oncology care teams. All patients and caregivers relied on social networks comprised of friends and family, although SGM patients and caregivers had smaller social networks and relied less on biological family, and single SGM individuals experienced challenges accessing cancer care and struggled with social isolation. We discovered too, that all caregivers, regardless of Sexual Orientation and Gender Identity (SOGI), perceived a lack of support and information pertaining to their loved one's treatment, side effects and best way to provide care. CONCLUSIONS: This study demonstrates that prior stigmatizing experiences contribute to minority stress and medical mistrust for SGM cancer patients and their informal caregivers across the cancer care experience. Findings point to specific gaps in SGM cancer patient care, including lack of conversation about patient SOGI, inadequate staff and oncology provider SGM specific knowledge and cultural competence/cultural humility training, and insufficient patient supports for those who lack social support during cancer care treatment. Further, this study reveals inadequacies in SGM specific support, and overall support services for informal cancer caregivers. Additional research is required to develop targeted interventions to address minority stress and clinic environment concerns to improve cancer care for SGM patients. Importantly, while there were differences between SGM and H/C experiences of cancer treatment, significant similarities also emerged. Caregiver expressed consensus about the current lack of support and guidance for informal caregivers of cancer patients. Future work should focus on providing caregiver-specific resources in the clinic setting and facilitating support groups for caregivers to network with one another, as well as for tailoring SGM specific caregiver support services. Our findings highlight areas for improving cancer care for the SGM community, as well as a broader population of patients and caregivers.
11[Influence of genetic factors on human sexual orientation. Review].PubMed
Alvaro Rodríguez-Larralde, Irene Paradisi
Invest Clin. 2009 Sep;50(3):377-91.
Human sexual orientation is a complex trait, influenced by several genes, experiential and sociocultural factors. These elements interact and produce a typical pattern of sexual orientation towards the opposite sex. Some exceptions exist, like bisexuality and homosexuality, which seem to be more frequent in males than females. Traditional methods for the genetic study of behavior multifactorial characteristics consist in detecting the presence of familial aggregation. In order to identify the importance of genetic and environmental factors in this aggregation, the concordance of the trait for monozygotic and dizygotic twins and for adopted sibs, reared together and apart, is compared. These types of studies have shown that familial aggregation is stronger for male than for female homosexuality. Based on the threshold method for multifactorial traits, and varying the frequency of homosexuality in the population between 4 and 10%, heritability estimates between 0.27 and 0.76 have been obtained. In 1993, linkage between homosexuality and chromosomal region Xq28 based on molecular approaches was reported. Nevertheless, this was not confirmed in later studies. Recently, a wide search of the genome has given significant or close to significant linkage values with regions 7q36, 8p12 and 10q26, which need to be studied more closely. Deviation in the proportion of X chromosome inactivation in mothers of homosexuals seems to favor the presence of genes related with sexual orientation in this chromosome. There is still much to be known about the genetics of human homosexuality.
12Sexual orientation, sexual identity, and sex-dimorphic behaviors in male twins.PubMed
N Buhrich, J M Bailey, N G Martin
Behav Genet. 1991 Jan;21(1):75-96. doi: 10.1007/BF01067668.
Sexual orientation, sexual identity, and sex-dimorphic behaviors were assessed concurrently and retrospectively, for childhood, in 95 pairs of male monozygotic (MZ) twins and 63 pairs of dizygotic (DZ) twins. There was a significantly higher rate of adult homosexuality among the MZ than among DZ twins. We employed a model-fitting approach using LISREL to test for genetic and environmental influences on variation for each trait singly and on the covariation among all six traits (three for childhood and three for adulthood). Univariate analyses confirmed the presence of familial factors for five of the six variables but were generally unable to distinguish shared environmental from genetic influences. Hierarchical tests of multivariate models supported the existence of an additive genetic factor contributing to the covariance among the variables. More restrictive multivariate models yielded a significant genetic influence on sexual orientation. Because of the different rates of orientation by zygosity and because of the restrictive nature of some of the multivariate models, our results are best considered tentative but do suggest that further biometrically oriented studies of sexual orientation and its correlates would be worthwhile.
13Human sexual orientation has a heritable component.PubMed
R C Pillard, J M Bailey
Hum Biol. 1998 Apr;70(2):347-65.
We present an overview of behavioral genetics research on homosexual and heterosexual orientation. Family, twin, and adoptee studies indicate that homosexuality and thus heterosexuality run in families. Sibling, twin, and adoptee concordance rates are compatible with the hypothesis that genes account for at least half of the variance in sexual orientation. We note observations of homosexual behavior in animal species, but the analogy to human sexual orientation is unclear. We discuss the reproductive disadvantage of a homosexual orientation and present possible mechanisms that could maintain a balanced polymorphism in human populations.
14Sexual Arousal Patterns of Identical Twins with Discordant Sexual Orientations.PubMed
Tuesday M Watts, Luke Holmes, Jamie Raines, et al.
Sci Rep. 2018 Oct 8;8(1):14970. doi: 10.1038/s41598-018-33188-2.
Genetically identical twins can differ in their self-reported sexual orientations. However, whether the twins' subjective reports reflect valid differences in their sexual orientations is unknown. Measures of sexual orientation, which are free of the limitations of self-report, include genital arousal and pupil dilation while viewing sexual stimuli depicting men or women. We examined these responses in 6 male twin pairs and 9 female twin pairs who reported discordant sexual orientations. Across measures, heterosexual male twins responded more strongly to women than to men. Their homosexual co-twins showed an opposite pattern. Heterosexual female twins responded equally to both sexes, whereas their homosexual co-twins responded somewhat more to women than men. These differences within pairs were similar to differences between unrelated heterosexual and homosexual males and females. Our study provides physiological evidence confirming twins' discordant sexual orientations, thereby supporting the importance of the non-shared environment for the development of sexual orientation and sexual arousal.
15Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior.PubMed
Andrea Ganna, Karin J H Verweij, Michel G Nivard, et al.
Science. 2019 Aug 30;365(6456). doi: 10.1126/science.aat7693.
Twin and family studies have shown that same-sex sexual behavior is partly genetically influenced, but previous searches for specific genes involved have been underpowered. We performed a genome-wide association study (GWAS) on 477,522 individuals, revealing five loci significantly associated with same-sex sexual behavior. In aggregate, all tested genetic variants accounted for 8 to 25% of variation in same-sex sexual behavior, only partially overlapped between males and females, and do not allow meaningful prediction of an individual's sexual behavior. Comparing these GWAS results with those for the proportion of same-sex to total number of sexual partners among nonheterosexuals suggests that there is no single continuum from opposite-sex to same-sex sexual behavior. Overall, our findings provide insights into the genetics underlying same-sex sexual behavior and underscore the complexity of sexuality.
16Probing the genomic landscape of human sexuality: a critical systematic review of the literature.PubMed
Nicola Luigi Bragazzi, Manlio Converti, Andrea Crapanzano, et al.
Front Genet. 2023 Aug 24;14:1184758. doi: 10.3389/fgene.2023.1184758. eCollection 2023.
Whether human sexuality is the result of nature or nurture (or their complex interplay) represents a hot, often ideologically driven, and highly polarized debate with political and social ramifications, and with varying, conflicting findings reported in the literature. A number of heritability and behavioral genetics studies, including pedigree-based investigations, have hypothesized inheritance patterns of human sexual behaviors. On the other hand, in most twin, adoption, and nuclear family studies, it was not possible to disentangle between underlying genetic and shared environmental sources. Furthermore, these studies were not able to estimate the precise extent of genetic loading and to shed light both on the number and nature of the putative inherited factors, which remained largely unknown. Molecular genetic studies offer an unprecedented opportunity to overcome these drawbacks, by dissecting the molecular basis of human sexuality and allowing a better understanding of its biological roots if any. However, there exists no systematic review of the molecular genetics of human sexuality. Therefore, we undertook this critical systematic review and appraisal of the literature, with the ambitious aims of filling in these gaps of knowledge, especially from the methodological standpoint, and providing guidance to future studies. Sixteen studies were finally retained and overviewed in the present systematic review study. Seven studies were linkage studies, four studies utilized the candidate gene approach, and five studies were GWAS investigations. Limitations of these studies and implications for further research are discussed.
17Discovery of new genetic loci for male sexual orientation in Han population.PubMed
Shao-Hua Hu, Hai-Mei Li, Hao Yu, et al.
Cell Discov. 2021 Oct 31;7(1):103. doi: 10.1038/s41421-021-00341-7.
Epidemiological studies have demonstrated that the genetic factors partly influence the development of same-sex sexual behavior, but most genetic studies have focused on people of primarily European ancestry, potentially missing important biological insights. Here, we performed a two-stage genome-wide association study (GWAS) with a total sample of 1478 homosexual males and 3313 heterosexual males in Han Chinese populations and identified two genetic loci (rs17320865, Xq27.3, FMR1NB, P = 8.36 × 10, OR = 1.29; rs7259428, 19q12, ZNF536, P = 7.58 × 10, OR = 0.75) showing consistent association with male sexual orientation. A fixed-effect meta-analysis including individuals of Han Chinese (n = 4791) and European ancestries (n = 408,995) revealed 3 genome-wide significant loci of same-sex sexual behavior (rs9677294, 2p22.1, SLC8A1, P = 1.95 × 10; rs2414487, 15q21.3, LOC145783, P = 4.53 × 10; rs2106525, 7q31.1, MDFIC, P = 6.24 × 10). These findings may provide new insights into the genetic basis of male sexual orientation from a wider population scope. Furthermore, we defined the average ZNF536-immunoreactivity (ZNF536-ir) concentration in the suprachiasmatic nucleus (SCN) as lower in homosexual individuals than in heterosexual individuals (0.011 ± 0.001 vs 0.021 ± 0.004, P = 0.013) in a postmortem study. In addition, compared with heterosexuals, the percentage of ZNF536 stained area in the SCN was also smaller in the homosexuals (0.075 ± 0.040 vs 0.137 ± 0.103, P = 0.043). More homosexual preference was observed in FMR1NB-knockout mice and we also found significant differences in the expression of serotonin, dopamine, and inflammation pathways that were reported to be related to sexual orientation when comparing CRISPR-mediated FMR1NB knockout mice to matched wild-type target C57 male mice.
18Genome-Wide Association Study of Male Sexual Orientation.PubMed
Alan R Sanders, Gary W Beecham, Shengru Guo, et al.
Sci Rep. 2017 Dec 7;7(1):16950. doi: 10.1038/s41598-017-15736-4.
Family and twin studies suggest that genes play a role in male sexual orientation. We conducted a genome-wide association study (GWAS) of male sexual orientation on a primarily European ancestry sample of 1,077 homosexual men and 1,231 heterosexual men using Affymetrix single nucleotide polymorphism (SNP) arrays. We identified several SNPs with p < 10, including regions of multiple supporting SNPs on chromosomes 13 (minimum p = 7.5 × 10) and 14 (p = 4.7 × 10). The genes nearest to these peaks have functions plausibly relevant to the development of sexual orientation. On chromosome 13, SLITRK6 is a neurodevelopmental gene mostly expressed in the diencephalon, which contains a region previously reported as differing in size in men by sexual orientation. On chromosome 14, TSHR genetic variants in intron 1 could conceivably help explain past findings relating familial atypical thyroid function and male homosexuality. Furthermore, skewed X chromosome inactivation has been found in the thyroid condition, Graves' disease, as well as in mothers of homosexual men. On pericentromeric chromosome 8 within our previously reported linkage peak, we found support (p = 4.1 × 10) for a SNP association previously reported (rs77013977, p = 7.1 × 10), with the combined analysis yielding p = 6.7 × 10, i.e., a genome-wide significant association.
19Sexual differentiation of the human hypothalamus: Relationship to gender identity and sexual orientation.PubMed
Dick F Swaab, Samantha E C Wolff, Ai-Min Bao
Handb Clin Neurol. 2021;181:427-443. doi: 10.1016/B978-0-12-820683-6.00031-2.
Gender identity (an individual's perception of being male or female) and sexual orientation (heterosexuality, homosexuality, or bisexuality) are programmed into our brain during early development. During the intrauterine period in the second half of pregnancy, a testosterone surge masculinizes the fetal male brain. If such a testosterone surge does not occur, this will result in a feminine brain. As sexual differentiation of the brain takes place at a much later stage in development than sexual differentiation of the genitals, these two processes can be influenced independently of each other and can result in gender dysphoria. Nature produces a great variability for all aspects of sexual differentiation of the brain. Mechanisms involved in sexual differentiation of the brain include hormones, genetics, epigenetics, endocrine disruptors, immune response, and self-organization. Furthermore, structural and functional differences in the hypothalamus relating to gender dysphoria and sexual orientation are described in this review. All the genetic, postmortem, and in vivo scanning observations support the neurobiological theory about the origin of gender dysphoria, i.e., it is the sizes of brain structures, the neuron numbers, the molecular composition, functions, and connectivity of brain structures that determine our gender identity or sexual orientation. There is no evidence that one's postnatal social environment plays a crucial role in the development of gender identity or sexual orientation.
20Sexual differentiation of the human brain in relation to gender identity and sexual orientation.PubMed
Ivanka Savic, Alicia Garcia-Falgueras, Dick F Swaab
Prog Brain Res. 2010;186:41-62. doi: 10.1016/B978-0-444-53630-3.00004-X.
It is believed that during the intrauterine period the fetal brain develops in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. According to this concept, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation should be programmed into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in transsexuality. This also means that in the event of ambiguous sex at birth, the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. There is no proof that social environment after birth has an effect on gender identity or sexual orientation. Data on genetic and hormone independent influence on gender identity are presently divergent and do not provide convincing information about the underlying etiology. To what extent fetal programming may determine sexual orientation is also a matter of discussion. A number of studies show patterns of sex atypical cerebral dimorphism in homosexual subjects. Although the crucial question, namely how such complex functions as sexual orientation and identity are processed in the brain remains unanswered, emerging data point at a key role of specific neuronal circuits involving the hypothalamus.
21Digit ratio (2D:4D) and congenital adrenal hyperplasia (CAH): Systematic literature review and meta-analysis.PubMed
Gareth Richards, Wendy V Browne, Ezra Aydin, et al.
Horm Behav. 2020 Nov;126:104867. doi: 10.1016/j.yhbeh.2020.104867. Epub 2020 Oct 6.
The ratio of length between the second and fourth fingers (2D:4D) is commonly used as an indicator of prenatal sex hormone exposure. Several approaches have been used to try to validate the measure, including examining 2D:4D in people with congenital adrenal hyperplasia (CAH), a suite of conditions characterised by elevated adrenal androgen production secondary to defective steroidogenesis. We present a systematic review and meta-analysis that examines the relationship between these two variables. Twelve articles relating to nine CAH cohorts were identified, and 2D:4D comparisons have been made between cases and controls in eight of these cohorts. Altogether, at least one 2D:4D variable has been compared between n = 251 females with CAH and n = 358 unaffected females, and between n = 108 males with CAH and n = 204 unaffected males. A previous meta-analysis (Hönekopp and Watson, 2010) reported lower right hand (R2D:4D) and left hand (L2D:4D) digit ratios in patients with CAH relative to sex-matched controls. Our meta-analysis showed the same pattern, with medium effect sizes for R2D:4D and small effect sizes for L2D:4D. Differences of small magnitude were also observed for M2D:4D, and no significant effects were observed for D. Notably, the only effects that remained statistically significant when stratified by sex were R2D:4D in males and L2D:4D in females, and the average effect size had reduced by 46.70% since the meta-analysis of Hönekopp and Watson (2010). We also found that individual comparisons in this literature were considerably underpowered, and that patterns of sexual dimorphism in 2D:4D were similar in CAH samples as in typically developing populations. Findings are discussed in relation to the prenatal androgen hypothesis as well as alternative explanations.
22Prenatal androgen-receptor activity has organizational morphological effects in mice.PubMed
Sabine E Huber, Bernd Lenz, Johannes Kornhuber, et al.
PLoS One. 2017 Nov 27;12(11):e0188752. doi: 10.1371/journal.pone.0188752. eCollection 2017.
Prenatal sex hormones exert organizational effects. It has been suggested that prenatal sex hormones affect adult morphological parameters, such as the finger length. Especially the second-to-fourth finger length (2D:4D) ratio has been implicated to be modified when exposed to higher androgen levels in utero. Here we show in a mouse model that experimental manipulation of the prenatal androgen level, by blocking the androgen receptor with flutamide or activating the androgen receptor with dihydrotestosterone (DHT), leads to changes in the length of the fingers of all paws in males and females. In addition to that, also total paw length and the 2D:4D ratio was affected. In males treated with DHT, the 2D:4D ratio was increased, while flutamide-treatment in females led to a reduced 2D:4D ratio. We also measured other parameters, such as head size, body length and tail length and demonstrate that body morphology is affected by prenatal androgen exposure with more prominent effects in females. Another factor that is thought to be influenced by early androgens is handedness. We tested mice for handedness, but did not find a significant effect of the prenatal treatment. These findings demonstrate that prenatal androgen activity is involved in the development of body morphology and might be a useful marker for prenatal androgen exposure.
23Through a glass, darkly: Human digit ratios reflect prenatal androgens, imperfectly.PubMed
Ashlyn Swift-Gallant, Brandon A Johnson, Victor Di Rita, et al.
Horm Behav. 2020 Apr;120:104686. doi: 10.1016/j.yhbeh.2020.104686. Epub 2020 Feb 6.
On average, the length of the index finger (digit 2) divided by the length of the ring finger (digit 4) on the right hand, is greater in women than in men. Converging evidence makes it clear that prenatal androgens affect the development of digit ratios in humans and so are likely responsible for this sex difference. Thus, differences in 2D:4D between groups within a sex may be due to average differences between those groups in prenatal androgen exposure. There have been many reports that lesbians, on average, have a smaller (more masculine) digit ratio than straight women, which has been confirmed by metaanalysis. These findings indicate that lesbians were, on average, exposed to greater prenatal androgen than straight women, which further indicates that greater levels of prenatal androgen predispose humans to be attracted to women in adulthood. Nevertheless, these results only apply to group differences between straight women and lesbians; digit ratios cannot be used to classify individual women as gay or straight.
24The relationship between finger length ratio, masculinity, and sexual orientation in women: A correlational study.PubMed
Luke Holmes, Tuesday M Watts-Overall, Erlend Slettevold, et al.
PLoS One. 2022 Mar 28;17(3):e0259637. doi: 10.1371/journal.pone.0259637. eCollection 2022.
Homosexual women are, on average, more masculine in their appearance and behavior than heterosexual women. We hypothesized that their masculinity was influenced by exposure to elevated levels of prenatal androgen during early development. We recruited 199 women (including 67 homosexual women) and measured their masculinity via self-report and observer ratings. Our measure of prenatal androgen exposure was the ratio of the index to ring finger (2D:4D), which is hypothesized to be lower in women exposed to elevated levels of androgens during prenatal development. Homosexual women were substantially more masculine than heterosexual women in both self-report and observer ratings. However, homosexual women neither had more male-typical finger length ratios, nor did their finger length ratios relate to their masculinity in any predicted direction. Thus, we found no evidence that increased prenatal androgen exposure influenced masculinity in homosexual women.
25Prenatal and adult androgen activities in alcohol dependence.PubMed
B Lenz, C Mühle, B Braun, et al.
Acta Psychiatr Scand. 2017 Jul;136(1):96-107. doi: 10.1111/acps.12725. Epub 2017 Apr 6.
OBJECTIVE: Alcohol dependence is more prevalent in men than in women. The evidence for how prenatal and adult androgens influence alcohol dependence is limited. We investigated the effects of prenatal and adult androgen activity on alcohol dependence. Moreover, we studied how the behaviours of pregnant women affect their children's prenatal androgen load. METHOD: We quantified prenatal androgen markers (e.g., second-to-fourth finger length ratio [2D : 4D]) and blood androgens in 200 early-abstinent alcohol-dependent in-patients and 240 controls (2013-2015, including a 12-month follow-up). We also surveyed 134 women during pregnancy (2005-2007) and measured the 2D : 4D of their children (2013-2016). RESULTS: The prenatal androgen loads were higher in the male alcohol-dependent patients compared to the controls (lower 2D : 4D, P = 0.004) and correlated positively with the patients' liver transaminase activities (P < 0.001) and alcohol withdrawal severity (P = 0.019). Higher prenatal androgen loads and increasing androgen levels during withdrawal predicted earlier and more frequent 12-month hospital readmission in alcohol-dependent patients (P < 0.005). Moreover, stress levels (P = 0.002), alcohol (P = 0.010) and tobacco consumption (P = 0.017), and lifetime stressors (P = 0.019) of women during pregnancy related positively to their children's prenatal androgen loads (lower 2D : 4D). CONCLUSION: Androgen activities in alcohol-dependent patients and behaviours of pregnant women represent novel preventive and therapeutic targets of alcohol dependence.
26The biological basis of sexual orientation: How hormonal, genetic, and environmental factors influence to whom we are sexually attracted.PubMed
Yan Wang, Haoda Wu, Zhong Sheng Sun
Front Neuroendocrinol. 2019 Oct;55:100798. doi: 10.1016/j.yfrne.2019.100798. Epub 2019 Oct 5.
Humans develop relatively stable attractions to sexual partners during maturation and present a spectrum of sexual orientation from homosexuality to heterosexuality encompassing varying degrees of bisexuality, with some individuals also displaying asexuality. Sexual orientation represents a basic life phenomenon for humans. However, the molecular mechanisms underlying these diverse traits of sexual orientation remain highly controversial. In this review, we systematically discuss recent advancements in sexual orientation research, including those related to measurements and associated brain regions. Current findings regarding sexual orientation modulation by hormonal, genetic, maternal immune system, and environmental factors are summarized in both human and model systems. We also emphasize that future studies should recognize the differences between males and females and pay more attention to minor traits and the epigenetic regulation of sexual orientation. A comprehensive view of sexual orientation may promote our understanding of the biological basis of sex, and that of human reproduction, and evolution.
27A difference in hypothalamic structure between heterosexual and homosexual men.PubMed
S LeVay
Science. 1991 Aug 30;253(5023):1034-7. doi: 10.1126/science.1887219.
The anterior hypothalamus of the brain participates in the regulation of male-typical sexual behavior. The volumes of four cell groups in this region [interstitial nuclei of the anterior hypothalamus (INAH) 1, 2, 3, and 4] were measured in postmortem tissue from three subject groups: women, men who were presumed to be heterosexual, and homosexual men. No differences were found between the groups in the volumes of INAH 1, 2, or 4. As has been reported previously, INAH 3 was more than twice as large in the heterosexual men as in the women. It was also, however, more than twice as large in the heterosexual men as in the homosexual men. This finding indicates that INAH is dimorphic with sexual orientation, at least in men, and suggests that sexual orientation has a biological substrate.
28Functional neuroanatomy and neuropathology of the human hypothalamus.PubMed
D F Swaab, M A Hofman, P J Lucassen, et al.
Anat Embryol (Berl). 1993 Apr;187(4):317-30. doi: 10.1007/BF00185889.
The human hypothalamus is involved in a wide range of functions in the developing, adult and aging subject and is responsible for a large number of symptoms of neuroendocrine, neurological and psychiatric diseases. In the present review some prominent hypothalamic nuclei are discussed in relation to normal development, sexual differentiation, aging and a number of neuropathological conditions. The suprachiasmatic nucleus, the clock of the brain, shows seasonal and circadian variations in its vasopressin neurons. During normal aging, but even more so in Alzheimer's disease, the number of these neurons decreases. In homosexual men this nucleus is larger than in heterosexual men. The difference between the sexually dimorphic nuclei of men and women arises between the ages of 2-4 to puberty. In adult men this nucleus is twice as large as in adult women. In the process of aging, a sex-dependent decrease in cell number occurs. The vasopressin and oxytocin cells of the supraoptic and paraventricular nucleus are present in adult numbers as early as mid-gestation. Lower oxytocin neuron numbers are found in Prader-Willi syndrome, AIDS and Parkinson's disease. Familial hypothalamic diabetes insipidus is based upon a point mutation in the vasopressin-neurophysin-glycopeptide gene. Parvicellular corticotropin-releasing hormone-containing neurons in the paraventricular nucleus increase in number and are activated during the course of aging. In post-menopausal women, the infundibular or arcuate nucleus contains hypertrophic neurons containing oestrogen receptors. These neurons may be involved in the initiation of menopausal flushes. The nucleus tuberalis lateralis may be involved in feeding behaviour and metabolism. In Huntington's disease the majority of its neurons is lost; in Alzheimer's disease it shows very strong cytoskeletal alterations. Tuberomammillary nucleus neurons contain, e.g., histamine or galanine, and project to the cortex. Strong cytoskeletal changes, as well as plaques and tangles are found in this nucleus in Alzheimer's disease. The various hypothalamic nuclei are probably involved in many functions and symptoms of which only a minority has been revealed.
29Cerebral sex dimorphism and sexual orientation.PubMed
Amirhossein Manzouri, Ivanka Savic
Hum Brain Mapp. 2018 Mar;39(3):1175-1186. doi: 10.1002/hbm.23908. Epub 2017 Dec 11.
The neurobiology of sexual orientation is frequently discussed in terms of cerebral sex dimorphism (defining both functional and structural sex differences). Yet, the information about possible cerebral differences between sex-matched homo and heterosexual persons is limited, particularly among women. In this multimodal MRI study, we addressed these issues by investigating possible cerebral differences between homo and heterosexual persons, and by asking whether there is any sex difference in this aspect. Measurements of cortical thickness (Cth), subcortical volumes, and functional and structural resting-state connections among 40 heterosexual males (HeM) and 40 heterosexual females (HeF) were compared with those of 30 homosexual males (HoM) and 30 homosexual females (HoF). Congruent with previous reports, sex differences were detected in heterosexual controls with regard to fractional anisotropy (FA), Cth, and several subcortical volumes. Homosexual groups did not display any sex differences in FA values. Furthermore, their functional connectivity was significantly less pronounced in the mesial prefrontal and precuneus regions. In these two particular regions, HoM also displayed thicker cerebral cortex than other groups, whereas HoF did not differ from HeF. In addition, in HoM the parietal Cth showed "sex-reversed" values, not observed in HoF. Homosexual orientation seems associated with a less pronounced sexual differentiation of white matter tracts and a less pronounced functional connectivity of the self-referential networks compared to heterosexual orientation. Analyses of Cth suggest that male and female homosexuality are not simple analogues of each other and that differences from heterosexual controls are more pronounced in HoM.
30The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group.PubMed
Sven C Mueller, Antonio Guillamon, Leire Zubiaurre-Elorza, et al.
J Sex Med. 2021 Jun;18(6):1122-1129. doi: 10.1016/j.jsxm.2021.03.079. Epub 2021 May 22.
BACKGROUND: In contrast to cisgender persons, transgender persons identify with a different gender than the one assigned at birth. Although research on the underlying neurobiology of transgender persons has been accumulating over the years, neuroimaging studies in this relatively rare population are often based on very small samples resulting in discrepant findings. AIM: To examine the neurobiology of transgender persons in a large sample. METHODS: Using a mega-analytic approach, structural MRI data of 803 non-hormonally treated transgender men (TM, n = 214, female assigned at birth with male gender identity), transgender women (TW, n = 172, male assigned at birth with female gender identity), cisgender men (CM, n = 221, male assigned at birth with male gender identity) and cisgender women (CW, n = 196, female assigned at birth with female gender identity) were analyzed. OUTCOMES: Structural brain measures, including grey matter volume, cortical surface area, and cortical thickness. RESULTS: Transgender persons differed significantly from cisgender persons with respect to (sub)cortical brain volumes and surface area, but not cortical thickness. Contrasting the 4 groups (TM, TW, CM, and CW), we observed a variety of patterns that not only depended on the direction of gender identity (towards male or towards female) but also on the brain measure as well as the brain region examined. CLINICAL TRANSLATION: The outcomes of this large-scale study may provide a normative framework that may become useful in clinical studies. STRENGTHS AND LIMITATIONS: While this is the largest study of MRI data in transgender persons to date, the analyses conducted were governed (and restricted) by the type of data collected across all participating sites. CONCLUSION: Rather than being merely shifted towards either end of the male-female spectrum, transgender persons seem to present with their own unique brain phenotype. Mueller SC, Guillamon A, Zubiaurre-Elorza L, et al. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021;18:1122-1129.
31Hostile home environment predicting early adolescent sexual harassment perpetration and potential school-related moderators.PubMed
Dorothy L Espelage, Christopher R Harper, Katherine M Ingram, et al.
J Res Adolesc. 2023 Jun;33(2):530-546. doi: 10.1111/jora.12823. Epub 2022 Dec 23.
Using family systems theory, this longitudinal study of middle school youth examined the effects of abuse, family conflict, and sibling aggression on sexual harassment perpetration (N = 1563; M 11.2, 51% boys; 39% Hispanic, 29% Black, and 19% White). Boys reported more sexual harassment than girls; perpetration increased for both. The association between a hostile home environment and sexual harassment perpetration was moderated by school experiences. School belonging buffered effects of hostile home environment on baseline sexual harassment perpetration for boys who experienced abuse and White adolescents with high sibling aggression. Academic grades moderated change in perpetration over time, but effects differed by sex and race. It is important to understand how early violence exposures relate to sexual violence perpetration during early adolescence.
32Mental health challenges within the LGBTQ community: A societal imperative.PubMed
Aman Shaikh, Prafull Kamble, Vandana Daulatabad, et al.
J Family Med Prim Care. 2024 Sep;13(9):3529-3535. doi: 10.4103/jfmpc.jfmpc_321_24. Epub 2024 Sep 11.
The LGBTQ community faces specific stressors rooted in societal discrimination, bias, and marginalization, impacting mental health significantly. Persistent discrimination, exclusion, and heteronormative expectations are identified as social determinants that contribute to heightened stress levels, resulting in increased rates of anxiety, depression, and suicidality. Moreover, the COVID-19 pandemic has also severely affected the physical and mental health of a large percentage of the population, particularly impacting the health of marginalized individuals such as LGBT individuals. Studies consistently reveal alarming mental health disparities between LGBTQ individuals and their heterosexual counterparts, with elevated rates of mood disorders, substance abuse, and self-harm. Transgender individuals, in particular, face unique challenges, including high rates of gender dysphoria and discrimination-induced mental distress. The concept of intersectionality within the LGBTQ community emphasizes the compounded burden faced by individuals with multiple marginalized identities, necessitating tailored mental health strategies. The societal context, including legal and policy frameworks, plays a pivotal role in shaping the mental health and scope for LGBTQ individuals. Supportive frameworks, such as anti-discrimination laws, marriage equality, and healthcare policies, contribute to societal acceptance and individual well-being. Additionally, efforts to destigmatize LGBTQ identities, comprehensive sex education, and public awareness campaigns challenging stereotypes are crucial for fostering a more inclusive societal mindset. Establishing robust support networks within the LGBTQ community, including initiatives providing mental health resources, counseling, community spaces, and allyship programs, is vital for community resilience. These efforts not only contribute to the well-being of individuals within the LGBTQ community but also work toward creating a more inclusive society. In conclusion, addressing mental health challenges within the LGBTQ community requires a multifaceted approach involving societal understanding, legal support, destigmatization efforts, and robust community resources. By acknowledging and comprehending the unique struggles faced by the LGBTQ community, society can collectively work toward building a more compassionate, supportive, and inclusive environment for all individuals, irrespective of their sexual orientation or gender identity.
33Sexual orientation and adolescent suicide attempt and self-harm: a co-twin control study.PubMed
Lauren M O'Reilly, Erik Pettersson, Kelly Donahue, et al.
J Child Psychol Psychiatry. 2021 Jul;62(7):834-841. doi: 10.1111/jcpp.13325. Epub 2020 Sep 14.
BACKGROUND: Research has demonstrated that individuals who identify as a sexual minority (e.g., gay/lesbian, bisexual) are at increased risk for suicidality-related outcomes. However, previous research is primarily limited by the lack of adjustment for unmeasured (i.e., genetic and environmental) confounding factors and previous psychopathology. METHODS: Using the Child and Adolescent Twin Study in Sweden, we employed a co-twin control design to examine the extent to which the association between sexual orientation and adolescent suicide attempt and self-harm (SA/SH) was independent of genetic and environmental factors shared by twins, as well as measured symptoms of childhood psychopathology. RESULTS: Adolescents who identified as a sexual minority (i.e., gay/lesbian, bisexual, or other sexual orientation) were at two-fold increased odds for SA/SH (OR, 2.01 [95% confidence interval, 1.63-2.49) compared to heterosexual adolescents. When adjusting for all genetic and shared environmental factors that make twins similar and for measured childhood psychopathology, the association remained positive but attenuated to OR, 1.55 (1.11-2.16). CONCLUSIONS: Identifying as a sexual minority was associated with approximately 50% increased odds of SA/SH in adolescence after adjusting for unmeasured genetic and environmental factors shared by twins and for childhood psychopathology. The results support that environmental factors specifically associated with identifying as a sexual minority likely increase risk for SA/SH. Our findings highlight the need to monitor suicidality risk among this group.
34Association Between Gender Minority Status and Mental Health in High School Students.PubMed
James White, Laurence Moore, Rebecca Cannings-John, et al.
J Adolesc Health. 2023 May;72(5):811-814. doi: 10.1016/j.jadohealth.2022.12.028. Epub 2023 Feb 19.
PURPOSE: Adolescence is a phase when young people begin to explore their gender identity. Adolescents who identify as a gender minority are vulnerable to experiencing mental health problems due to stigmatization of their identity. METHODS: A population-wide study compared gender minority and cisgender students (aged 13-14 years) self-reported symptoms of probable depression, anxiety, and conduct disorder, and auditory hallucinations, including the distress and frequency of hallucinations. RESULTS: Gender minority students compared to cisgender students had four times the odds of reporting a probable depressive disorder, anxiety disorder, auditory hallucinations, but not conduct disorder. Of those who reported a hallucination, gender minority students were more likely to report hearing them daily but were no more likely to find them distressing. DISCUSSION: Gender minority students experience a disproportionate burden of mental health problems. Services and programming should be adapted to better support gender minority high-school students.
35Reducing LGBTQ+ adolescent mental health inequalities: a realist review of school-based interventions.PubMed
Elizabeth McDermott, Alex Kaley, Eileen Kaner, et al.
J Ment Health. 2024 Dec;33(6):768-778. doi: 10.1080/09638237.2023.2245894. Epub 2023 Aug 17.
BACKGROUND: LGBTQ+ young people have elevated rates of poor mental health in comparison to their cisgender heterosexual peers. School environment is a key risk factor and consistently associated with negative mental health outcomes for LGBTQ+ adolescents. AIMS: To examine how, why, for whom and in what context school-based interventions prevent or reduce mental health problems in LGBTQ+ adolescents. METHODS: A realist review methodology was utilised and focused on all types of school-based interventions and study designs. A Youth Advisory Group were part of the research team. Multiple search strategies were used to locate relevant evidence. Studies were subject to inclusion criteria and quality appraisal, and included studies were synthesised to produce a programme theory. Seventeen studies were included in the review. RESULTS: Eight intervention components were necessary to address LGBTQ+ pupils mental health: affirmative visual displays; external signposting to LGBTQ+ support; stand-alone input; school-based LGBTQ support groups; curriculum-based delivery; staff training; inclusion policies; trusted adult. Few school-based interventions for this population group were identified. CONCLUSIONS: The programme theory indicates that "to work" school-based interventions must have a "whole-school" approach that addresses specifically the dominant cis-heteronormative school environment and hence the marginalisation, silence, and victimisation that LGBTQ+ pupils can experience.
36Introduction: transnational lesbian cultures.PubMed
Heike Bauer, Churnjeet Mahn
J Lesbian Stud. 2014;18(3):203-8. doi: 10.1080/10894160.2014.896608.
This special issue examines the transnational shape and shaping of lesbian lives and cultures in and across China, India, the United Kingdom, and the United States. It uses the expression "transnational lesbian cultures" to suggest that despite sometimes radically different sociopolitical and cultural contexts, the lived experiences of same-sex desire and their emotional attachments create particular affinities between women who love women, affinities that reach across the distinct cultural and social contexts that shape them. The articles brought together explore lesbian subcultures, film, graphic novels, music, and online intimacies. They show that as a cultural and political signifier and as an analytical tool, lesbian troubles and complicates contemporary sexual politics, not least by revealing some of the gendered structures that shape debates about sexuality in a range of critical, cultural and political contexts. While the individual pieces cover a wide range of issues and concerns-which are often highly specific to the historical, cultural, and political contexts they discuss-together they tell a story about contemporary transnational lesbian culture: one that is marked by intricate links between norms and their effects and shaped by the efforts to resist denial, discrimination, and sometimes even active persecution.
37Adolescent Sexuality.PubMed
Jessica R Long, Lauren F Damle
Obstet Gynecol Clin North Am. 2024 Jun;51(2):299-310. doi: 10.1016/j.ogc.2024.02.004. Epub 2024 Apr 4.
Adolescence is a unique time where there are many developmental changes occurring. Teenagers are striving to establish their personal identity as they are also developing a better understanding of their gender and sexual identity while navigating social expectations both in person and online. Therefore, clinicians must continue to support adolescent patients and their families by providing accurate and timely information so that they can have the tools they need to avoid the pitfalls of an uninformed adolescent experience.
38Development, risk, and resilience of transgender youth.PubMed
Kimberly A Stieglitz
J Assoc Nurses AIDS Care. 2010 May-Jun;21(3):192-206. doi: 10.1016/j.jana.2009.08.004. Epub 2010 Mar 29.
Transgender youth face unique and complex issues as they confront cultural expectations of gender expression and how these fit with what is natural for them. Striving for balance, learning to cope, questioning, and eventually becoming comfortable with one's gender identity and sexual orientation are of paramount importance for healthy growth and development. Ineffective management of intense challenges over time without adequate social support places youth at risk for a number of unhealthy behaviors, including risk behaviors associated with acquiring HIV. This article explores early foundations of gender identity development, challenges in the development of transgender youth, and the limited data that exist on transgender youth and HIV risks. The concept of resilience is introduced as a counterbalancing area for assessment and intervention in practice and future research with transgender youth.
39The scientific pursuit of sexual and gender minority mental health treatments: Toward evidence-based affirmative practice.PubMed
John E Pachankis
Am Psychol. 2018 Dec;73(9):1207-1219. doi: 10.1037/amp0000357.
The time has arrived for psychological science to translate the accumulating empirical research regarding sexual and gender minority (SGM) mental health into evidence-based affirmative treatments for this population. Far from the unscientific, homophobic theories of the early 20th century, several recent efforts in psychological science are starting to pave the way for evidence-based SGM-affirmative mental health treatments. These efforts include (a) identifying clear treatment targets for SGM, (b) conducting treatment studies that test the efficacy of therapy for SGM populations, (c) increased reporting of sexual orientation and gender diversity in existing randomized controlled trials conducted with the general population, and (d) reducing stigma itself, which has heretofore impeded the resources necessary to produce scientific evidence about SGM-affirmative treatments. This article reviews this progress and outlines future research directions needed to advance evidence-based practice for SGM, including determining whether and how existing evidence-based treatments need to be adapted to address SGM-specific concerns, why SGM-affirmative treatments work, and for whom and under what conditions SGM-affirmative treatments work best. A program of research is described that attempts to address these questions through randomized controlled trials with strong comparison conditions, psychotherapy process research of current SGM-affirmative practice, and tests of treatment moderators. To the extent that the mental health profession continues to pursue these solutions, it can ensure the continued flourishing of this population, whose visibility and vibrancy likely represent the surest route toward improving public acceptance and therefore its future mental health. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
40Promotion of tobacco use cessation for lesbian, gay, bisexual, and transgender people: a systematic review.PubMed
Joseph G L Lee, Alicia K Matthews, Cramer A McCullen, et al.
Am J Prev Med. 2014 Dec;47(6):823-31. doi: 10.1016/j.amepre.2014.07.051. Epub 2014 Nov 18.
CONTEXT: Lesbian, gay, bisexual, and transgender (LGBT) people are at increased risk for the adverse effects of tobacco use, given their high prevalence of use, especially smoking. Evidence regarding cessation is limited. To determine if efficacious interventions are available and to aid the development of interventions, a systematic review was conducted of grey and peer-reviewed literature describing clinical, community, and policy interventions, as well as knowledge, attitudes, and behaviors regarding tobacco use cessation among LGBT people. EVIDENCE ACQUISITION: Eight databases for articles from 1987 to April 23, 2014, were searched. In February-November 2013, authors and researchers were contacted to identify grey literature. EVIDENCE SYNTHESIS: The search identified 57 records, of which 51 were included and 22 were from the grey literature; these were abstracted into evidence tables, and a narrative synthesis was conducted in October 2013-May 2014. Group cessation curricula tailored for LGBT populations were found feasible to implement and show evidence of effectiveness. Community interventions have been implemented by and for LGBT communities, although these interventions showed feasibility, no rigorous outcome evaluations exist. Clinical interventions show little difference between LGBT and heterosexual people. Focus groups suggest that care is needed in selecting the messaging used in media campaigns. CONCLUSIONS: LGBT-serving organizations should implement existing evidence-based tobacco-dependence treatment and clinical systems to support treatment of tobacco use. A clear commitment from government and funders is needed to investigate whether sexual orientation and gender identity moderate the impacts of policy interventions, media campaigns, and clinical interventions.
41Genetic and environmental influences on female sexual orientation, childhood gender typicality and adult gender identity.PubMed
Andrea Burri, Lynn Cherkas, Timothy Spector, et al.
PLoS One. 2011;6(7):e21982. doi: 10.1371/journal.pone.0021982. Epub 2011 Jul 7.
BACKGROUND: Human sexual orientation is influenced by genetic and non-shared environmental factors as are two important psychological correlates--childhood gender typicality (CGT) and adult gender identity (AGI). However, researchers have been unable to resolve the genetic and non-genetic components that contribute to the covariation between these traits, particularly in women. METHODOLOGY/PRINCIPAL FINDINGS: Here we performed a multivariate genetic analysis in a large sample of British female twins (N = 4,426) who completed a questionnaire assessing sexual attraction, CGT and AGI. Univariate genetic models indicated modest genetic influences on sexual attraction (25%), AGI (11%) and CGT (31%). For the multivariate analyses, a common pathway model best fitted the data. CONCLUSIONS/SIGNIFICANCE: This indicated that a single latent variable influenced by a genetic component and common non-shared environmental component explained the association between the three traits but there was substantial measurement error. These findings highlight common developmental factors affecting differences in sexual orientation.
42Genetic and environmental effects on same-sex sexual behavior: a population study of twins in Sweden.PubMed
Niklas Långström, Qazi Rahman, Eva Carlström, et al.
Arch Sex Behav. 2010 Feb;39(1):75-80. doi: 10.1007/s10508-008-9386-1. Epub 2008 Jun 7.
There is still uncertainty about the relative importance of genes and environments on human sexual orientation. One reason is that previous studies employed self-selected, opportunistic, or small population-based samples. We used data from a truly population-based 2005-2006 survey of all adult twins (20-47 years) in Sweden to conduct the largest twin study of same-sex sexual behavior attempted so far. We performed biometric modeling with data on any and total number of lifetime same-sex sexual partners, respectively. The analyses were conducted separately by sex. Twin resemblance was moderate for the 3,826 studied monozygotic and dizygotic same-sex twin pairs. Biometric modeling revealed that, in men, genetic effects explained .34-.39 of the variance, the shared environment .00, and the individual-specific environment .61-.66 of the variance. Corresponding estimates among women were .18-.19 for genetic factors, .16-.17 for shared environmental, and 64-.66 for unique environmental factors. Although wide confidence intervals suggest cautious interpretation, the results are consistent with moderate, primarily genetic, familial effects, and moderate to large effects of the nonshared environment (social and biological) on same-sex sexual behavior.
43Neurobiology of gender identity and sexual orientation.PubMed
C E Roselli
J Neuroendocrinol. 2018 Jul;30(7):e12562. doi: 10.1111/jne.12562.
Sexual identity and sexual orientation are independent components of a person's sexual identity. These dimensions are most often in harmony with each other and with an individual's genital sex, although not always. The present review discusses the relationship of sexual identity and sexual orientation to prenatal factors that act to shape the development of the brain and the expression of sexual behaviours in animals and humans. One major influence discussed relates to organisational effects that the early hormone environment exerts on both gender identity and sexual orientation. Evidence that gender identity and sexual orientation are masculinised by prenatal exposure to testosterone and feminised in it absence is drawn from basic research in animals, correlations of biometric indices of androgen exposure and studies of clinical conditions associated with disorders in sexual development. There are, however, important exceptions to this theory that have yet to be resolved. Family and twin studies indicate that genes play a role, although no specific candidate genes have been identified. Evidence that relates to the number of older brothers implicates maternal immune responses as a contributing factor for male sexual orientation. It remains speculative how these influences might relate to each other and interact with postnatal socialisation. Nonetheless, despite the many challenges to research in this area, existing empirical evidence makes it clear that there is a significant biological contribution to the development of an individual's sexual identity and sexual orientation.
44Sexual partner preference in animals and humans.PubMed
Jacques Balthazart
Neurosci Biobehav Rev. 2020 Aug;115:34-47. doi: 10.1016/j.neubiorev.2020.03.024. Epub 2020 May 22.
Sex differences in brain and behavior of animals including humans result from an interaction between biological and environmental influences. This is also true for the differences between men and women concerning sexual orientation. Sexual differentiation is mediated by three groups of biological mechanisms: early actions of sex steroids, more direct actions of sex-specific genes not mediated by gonadal sex steroids and epigenetic mechanisms. Differential interactions with parents and conspecifics have additionally long-term influences on behavior. This presentation reviews available evidence indicating that these different mechanisms play a significant role in the control of sexual partner preference in animals and humans, in other words the homosexual versus heterosexual orientation. Clinical and epidemiological studies of phenotypically selected populations indicate that early actions of hormones and genetic factors clearly contribute to the determination of sexual orientation. The maternal embryonic environment also modifies the incidence of male homosexuality via immunological mechanisms. The relative contribution of each of these mechanisms remains however to be determined.
45Molecular aspects of sexual differentiation of the rodent brain.PubMed
M M McCarthy
Psychoneuroendocrinology. 1994;19(5-7):415-27. doi: 10.1016/0306-4530(94)90029-9.
The sexual differentiation of the brain is orchestrated by gonadal steroids during a restricted developmental period and results in permanent changes in the neural substrate including the capacity to support ovulation and expression of sex-specific reproductive behaviors. Sry gene-induced development of testes constitutes a binary switch directing all subsequent differentiation. Androgen produced by the testes of the embryonic male differentiates secondary sex characteristics but also acts in the brain to "masculinize" the neural substrate, many of the latter are the result of aromatization of testosterone to estrogen. Molecular characteristics of aromatase and 5 alpha-reductase enzymes are reviewed. It is assumed that estrogen binds to its receptor which then binds to DNA, inducing transcription of specific genes. Mutations in steroid receptor genes can markedly alter hormone-mediated differentiation. Two questions are addressed: (1), is the assumption correct that estrogen's effects on sexual differentiation are via the classic genomic action of steroids?; and (2) if so, what genes are transcribed as a result of the activated estrogen receptor complex? We have used antisense oligodeoxynucleotides designed to hybridize with and block the translation of mRNA for the estrogen receptor. Administration of antisense into brain of 3-day-old pups had permanent effects on estrogen-induced differentiation as indicated by behavioral and brain morphology differences in adulthood. These results demonstrate the effectiveness of antisense oligonucleotides if administered during a critical period and further confirm the widely accepted tenet that estrogen acts on the brain via its receptor. Subsequent experiments can now address the question of what genes are being activated by the estrogen receptor during development.
46Adolescent homosexuality.PubMed
S M Stronski Huwiler, G Remafedi
Adv Pediatr. 1998;45:107-44.
Homosexuality has existed in all civilizations, but societal disapproval and cultural taboos have negatively influenced its recognition. A significant percentage of youths identify themselves as homosexual, and even more experience sex with the same sex or are confused about sexual feelings. A unifying etiological theory attributes the expression of sexual orientation to genes that shape the central nervous system's development, organization, and structure via prenatal sex steroids. Environmental factors may influence the expression of genetic potential. Several models of psychosocial development describe initial stages of awareness and confusion about same-sex attractions, followed by acknowledgement of homosexuality, disclosure to others, and eventual integration of sexual identity into a comprehensive sense of self. Stressors related to isolation, stigma, and violence may predispose homosexual adolescents to impaired social, emotional, and physical health, resulting in depression and suicide, school problems, substance abuse, running away eating disorders, risky sexual behavior, and illegal conduct. As with all adolescents, the overall goals in the care of homosexual youth are to promote normal adolescent development, social and emotional well-being, and physical health. A comprehensive, multidisciplinary approach is required to address medical, mental health, and psychosocial issues within the context of the adolescents' community and culture.
47The biological basis of human sexual orientation: is there a role for epigenetics?PubMed
Tuck C Ngun, Eric Vilain
Adv Genet. 2014;86:167-84. doi: 10.1016/B978-0-12-800222-3.00008-5.
Sexual orientation is one of the largest sex differences in humans. The vast majority of the population is heterosexual, that is, they are attracted to members of the opposite sex. However, a small but significant proportion of people are bisexual or homosexual and experience attraction to members of the same sex. The origins of the phenomenon have long been the subject of scientific study. In this chapter, we will review the evidence that sexual orientation has biological underpinnings and consider the involvement of epigenetic mechanisms. We will first discuss studies that show that sexual orientation has a genetic component. These studies show that sexual orientation is more concordant in monozygotic twins than in dizygotic ones and that male sexual orientation is linked to several regions of the genome. We will then highlight findings that suggest a link between sexual orientation and epigenetic mechanisms. In particular, we will consider the case of women with congenital adrenal hyperplasia (CAH). These women were exposed to high levels of testosterone in utero and have much higher rates of nonheterosexual orientation compared to non-CAH women. Studies in animal models strongly suggest that the long-term effects of hormonal exposure (such as those experienced by CAH women) are mediated by epigenetic mechanisms. We conclude by describing a hypothetical framework that unifies genetic and epigenetic explanations of sexual orientation and the continued challenges facing sexual orientation research.
48The molecular mechanisms of sexual orientation and gender identity.PubMed
Alessandra D Fisher, Jiska Ristori, Girolamo Morelli, et al.
Mol Cell Endocrinol. 2018 May 15;467:3-13. doi: 10.1016/j.mce.2017.08.008. Epub 2017 Aug 25.
Differences between males and females are widely represented in nature. There are gender differences in phenotypes, personality traits, behaviors and interests, cognitive performance, and proneness to specific diseases. The most marked difference in humans is represented by sexual orientation and core gender identity, the origins of which are still controversial and far from being understood. Debates continue on whether sexual behavior and gender identity are a result of biological (nature) or cultural (nurture) factors, with biology possibly playing a major role. The main goal of this review is to summarize the studies available to date on the biological factors involved in the development of both sexual orientation and gender identity. A systematic search of published evidence was performed using Medline (from January 1948 to June 2017). Review of the relevant literature was based on authors' expertise. Indeed, different studies have documented the possible role and interaction of neuroanatomic, hormonal and genetic factors. The sexual dimorphic brain is considered the anatomical substrate of psychosexual development, on which genes and gonadal hormones may have a shaping effect. In particular, growing evidence shows that prenatal and pubertal sex hormones permanently affect human behavior. In addition, heritability studies have demonstrated a role of genetic components. However, a convincing candidate gene has not been identified. Future studies (e.i. genome wide studies) are needed to better clarify the complex interaction between genes, anatomy and hormonal influences on psychosexual development.
49Gender/Sex, Sexual Orientation, and Identity Are in the Body: How Did They Get There?PubMed
Anne Fausto-Sterling
J Sex Res. 2019 May-Jun;56(4-5):529-555. doi: 10.1080/00224499.2019.1581883. Epub 2019 Mar 15.
In this review, I explore theoretical and empirical approaches to the development of gender/sex and sexual orientation (SO). Leaving behind the nature versus nurture opposition, I look at both identities as deeply embodied. My approach intertwines sex, gender, orientation, bodies, and cultures without a demand to choose one over the other. First, I introduce basic definitions, focusing on how intertwined the concepts of sex and gender really are. I affirm recent trends to consider a new term-gender/sex-as the best way to think about these deeply interwoven bodily traits. I introduce several literatures, each of which considers the processes by which traits become embodied. These points of view offer a basis for future work on identity development. Specifically, and selectively, I provide insights from the fields of phenomenology, dyadic interaction and the formation of presymbolic representations in infancy, and dynamic systems in infant development. I consider how thinking about embodied cognition helps to address intersubjectivity and the emergence of subjective identity. Next, I review what we currently know about the development of complex sexual systems in infancy and toddlerhood. Finally, I discuss the few existing theories of SO development that consider the events of infancy and childhood.
50Sexual orientation and adolescent substance use: a meta-analysis and methodological review.PubMed
Michael P Marshal, Mark S Friedman, Ron Stall, et al.
Addiction. 2008 Apr;103(4):546-56. doi: 10.1111/j.1360-0443.2008.02149.x.
AIMS: Several decades of research have shown that lesbian, gay and bisexual (LGB) adults are at high risk for substance use and substance use disorders (SUDs). These problems may often start prior to young adulthood; however, relatively little is known about risk for substance use in LGB adolescents. The primary aims of this paper were to conduct a meta-analysis of the relationship between sexual orientation and adolescent substance use and a systematic review and critique of the methodological characteristics of this literature. METHODS: Medical and social science journals were searched using Medline and PsychInfo. Studies were included if they tested the relationship between sexual orientation and adolescent substance use. Eighteen published studies were identified. Data analysis procedures followed expert guidelines, and used National Institutes of Health (NIH)-sponsored meta-analysis software. RESULTS: LGB adolescents reported higher rates of substance use compared to heterosexual youth (overall odds ratio = 2.89, Cohen's d = 0.59). Effect sizes varied by gender, bisexuality status, sexual orientation definition and recruitment source. None of the studies tested mediation and only one tested moderation. One employed a matched comparison group design, one used a longitudinal design, and very few controlled for possible confounding variables. CONCLUSIONS: The odds of substance use for LGB youth were, on average, 190% higher than for heterosexual youth and substantially higher within some subpopulations of LGB youth (340% higher for bisexual youth, 400% higher for females). Causal mechanisms, protective factors and alternative explanations for this effect, as well as long-term substance use outcomes in LGB youth, remain largely unknown.
51Everyday Sexual and Gender Minority Stress and Health: A Systematic Review of Experience Sampling Studies.PubMed
Julia Nicholas, Konrad Bresin
Arch Sex Behav. 2024 Apr;53(4):1221-1243. doi: 10.1007/s10508-023-02779-0. Epub 2024 Jan 3.
Sexual and gender minority stress is associated with negative physical and mental health outcomes, such as hypertension and depression. Expanding on previous reviews of the literature on cross-sectional and long-term prospective associations between sexual and gender minority stress and health outcomes, the current systematic review synthesizes the evidence on how everyday sexual and gender minority stress relates to momentary changes in health. The findings of 53 experience sampling studies published between 2007 and 2022 suggest that daily and momentary within-persons fluctuations in minority stressors are associated with cognitive-emotional (e.g., affect, suicidality), behavioral (e.g., substance use), social (e.g., relationship satisfaction), and physical health outcomes (e.g., somatic symptoms). These findings suggest that sexual and gender minority stress is a dynamic process that can vary within individuals over time and significantly impact everyday mental and physical health. We discuss the implications of these findings for minority stress theory, LGBTQ+ health research, LGBTQ+ affirming therapy, and prevention initiatives. The current experience sampling literature is limited by a lack of attention to gender minority stress and a focus on a limited range of health outcomes. Methodological and theoretical considerations for future experience sampling research are discussed in light of these limitations.
52Sexual Dysfunction in Men Who Have Sex With Men.PubMed
Philip J Cheng
Sex Med Rev. 2022 Jan;10(1):130-141. doi: 10.1016/j.sxmr.2021.01.002. Epub 2021 Apr 27.
INTRODUCTION: Historically, sexual health research has focused on men who have sex with women (MSW) and most research examining the sexual health of men who have sex with men (MSM) has focused on HIV transmission. Despite a high prevalence of sexual health disorders among MSM, there is limited research that has evaluated the diversity of sexual issues in these patients. OBJECTIVES: The purpose of this review is to describe the unique sexual behaviors, concerns, and dysfunctions of MSM by evaluating the literature on sexual health in this specific patient population. METHODS: A PubMed literature search was conducted through December 2020 to identify all relevant publications related to the sexual health, sexual practices, and sexual dysfunction of MSM. Original research, review articles, and meta-analyses were reviewed, including comparisons of sexual behavior and dysfunction between MSM and non-MSM populations and between gay/bisexual men and heterosexual men. Approximately 150 relevant articles were reviewed and 100 were included in the manuscript. RESULTS: Minority stress can lead to an increase in high-risk sexual behavior, sexual dysfunction, and mental health disorders in MSM. MSM engage in a variety of sexual behaviors, which can lead to differences in sexual dysfunction, such as anodyspareunia during receptive anal intercourse. MSM have higher rates of erectile dysfunction than non-MSM counterparts. MSM have unique activators of sexual pathologies, such as insertive anal intercourse for Peyronie's disease. Prostate cancer treatment may cause MSM to change sexual roles and practices following treatment due to ED, anodyspareunia, or decrease in pleasure from receptive anal intercourse after prostatectomy. CONCLUSION: MSM have been neglected from sexual medicine research, which translates to disparities in health care. Further research that focuses on the MSM population is necessary to better educate healthcare practitioners so that MSM patients can receive adequate care that is tailored to their specific needs. Cheng PJ, Sexual Dysfunction in Men Who Have Sex With Men. Sex Med Rev 2022;10:130-141.
53A short review of biological research on the development of sexual orientation.PubMed
Anthony F Bogaert, Malvina N Skorska
Horm Behav. 2020 Mar;119:104659. doi: 10.1016/j.yhbeh.2019.104659. Epub 2020 Jan 8.
We review research supporting biological mechanisms in the development of sexual orientation. This research includes studies on neural correlates, prenatal hormones and related physical/behavioral correlates, genetics, and the fraternal birth order effect (FBOE). These studies, taken together, have provided substantial support for biological influences underlying the development of sexual orientation, but questions remain unanswered, including how biological mechanisms may differ in contributing to men's and women's sexual orientation development.
54Mental Health Disparities by Sexual Orientation and Gender Identity in the All of Us Research Program.PubMed
Junjie Anderson Lu, Shamsi Soltani, S Bryn Austin, et al.
JAMA Netw Open. 2025 Jan 2;8(1):e2456264. doi: 10.1001/jamanetworkopen.2024.56264.
IMPORTANCE: Limited research explores mental health disparities between individuals in sexual and gender minority (SGM) populations and cisgender heterosexual (non-SGM) populations using national-level data. OBJECTIVE: To explore mental health disparities between SGM and non-SGM populations across sexual orientation, sex assigned at birth, and gender identity within the All of Us Research Program. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used survey data and linked electronic health records of eligible All of Us Research Program participants from May 31, 2017, to June 30, 2022. EXPOSURE: Self-identified SGM status. MAIN OUTCOMES AND MEASURES: Prevalence of common mental health conditions identified from linked electronic health records. Logistic regression adjusted for age, race and ethnicity, educational level, income, employment status, and geographic region was used to assess the association between SGM status and mental health conditions. RESULTS: Among 413 457 participants, 269 947 (65.3%) were included in the analysis (median age, 59 [IQR, 43-70] years), with 22 189 (8.2%) self-identified as SGM. Men with cisgender sexual minority identity had higher odds of bipolar disorder (adjusted odds ratio [AOR], 1.87; 95% CI, 1.70-2.56) compared with cisgender heterosexual men. Women with cisgender sexual minority identity had higher odds of bipolar disorder (AOR, 2.09; 95% CI, 1.95-2.25) compared with cisgender heterosexual women. Gender diverse people assigned female sex at birth had higher odds of posttraumatic stress disorder (PTSD) compared with both cisgender heterosexual men (AOR, 3.67; 95% CI, 2.99-4.50) and cisgender heterosexual women (AOR, 2.77; 95% CI, 2.26-3.40). Gender diverse individuals assigned male sex at birth had higher odds of bipolar disorder (AOR, 2.35; 95% CI, 1.66-3.33) compared with cisgender heterosexual men and higher odds of attention-deficit/hyperactivity disorder (AOR, 2.19; 95% CI, 1.48-3.23) compared with cisgender heterosexual women. Transgender men had higher odds of depression (AOR, 2.11; 95% CI, 1.80-2.49) compared with cisgender heterosexual men, while transgender women had higher odds of any personality disorder (AOR, 2.71; 95% CI, 1.84-3.99) compared with cisgender heterosexual women. CONCLUSIONS AND RELEVANCE: In this cross-sectional study of participants in the All of Us Research Program, there were significant mental health disparities between participants in SGM and non-SGM groups. These findings underscore the need for tailored mental health interventions to improve the well-being of SGM populations, while noting that the associations do not imply causality but reflect the stigma and minority stress experienced by these individuals.
55Sexual orientation and mental health.PubMed
Gregory M Herek, Linda D Garnets
Annu Rev Clin Psychol. 2007;3:353-75. doi: 10.1146/annurev.clinpsy.3.022806.091510.
This article provides an overview of current psychological research on mental health and sexual orientation, as well as clinical practice with sexual minorities. The historical context for current research questions and controversies is described, and the findings of recent empirical research on psychological well-being and distress among nonheterosexuals are summarized. The minority stress model is used to frame a discussion of stressors unique to sexual minorities and to consider their possible effects on psychological well-being. The possible ameliorative effects of adopting a sexual orientation identity are examined, followed by a discussion of how these ideas translate into contemporary clinical work with sexual minority clients. The review concludes with a brief discussion of priority areas for empirical research and clinical practice.
56Rumination mediates the associations between sexual minority stressors and disordered eating, particularly for men.PubMed
Shirley B Wang, Ashley Borders
Eat Weight Disord. 2017 Dec;22(4):699-706. doi: 10.1007/s40519-016-0350-0. Epub 2016 Dec 30.
PURPOSE: Sexual minority individuals experience unique minority stressors leading to negative clinical outcomes, including disordered eating. The psychological mediation framework posits that stress related to discrimination, internalized homonegativity, and concealment makes sexual minority individuals more vulnerable to maladaptive coping processes, such as rumination, known to predict disordered eating. The current study examined the influence of sexual minority stressors and rumination on disordered eating, and whether these associations differed between sexual minority men and women. We hypothesized that perceived discrimination, internalized homonegativity, and concealment would be positively associated with disordered eating, and that rumination about sexual minority stigma would mediate these associations. METHODS: One-hundred and sixteen individuals who identified as sexual minorities completed a survey study assessing perceived discrimination, internalized homonegativity, concealment, rumination about sexual minority stigma, and disordered eating. RESULTS: Discrimination and concealment uniquely predicted disordered eating in both men and women. However, rumination emerged as a significant mediator for concealment and (marginally) for discrimination for men only. Internalized homonegativity was not uniquely associated with rumination or disordered eating for men or women. CONCLUSIONS: Sexual minority men who experience discrimination and conceal their sexual orientation may engage in more disordered eating because they dwell on sexual minority stigma. We propose other potential mechanisms that may be relevant for sexual minority women.
57Sexualization of Children or Human Rights? Attitudes Toward Addressing Sexual-Orientation Diversity in School.PubMed
Ulrich Klocke
J Homosex. 2024 Feb 23;71(3):600-631. doi: 10.1080/00918369.2022.2122368. Epub 2022 Oct 17.
Lesbian, gay, and bisexual (LGB) adolescents are more likely to experience mental health problems than their heterosexual peers because they are victimized more often or fear discrimination. Governmental plans to improve this situation by addressing sexual diversity in German schools have been accompanied by public resistance and misinformation, e.g., that they aim to sexualize children. The present study assessed how widespread negative attitudes toward such plans really are and how they can be explained. A random sample of 2,013 German residents was surveyed by phone. Only 10% opposed promoting acceptance of LGB in school. Approval of such plans was predominantly predicted by respondents' beliefs about sexual orientation and the plans' aim, and only marginally by societal values. Respondents who knew that the plans' aim was to promote acceptance of LGB and not to sexualize children and that children with same-sex parents are just as well off as those with heterosexual parents showed higher approval, whereas respondents who believed that homosexuality is affected by socialization showed higher opposition.
58Meeting the health and social care needs of LGBT+ people.PubMed
Ben Heyworth
Nurs Stand. 2023 Feb 1;38(2):27-33. doi: 10.7748/ns.2023.e12032. Epub 2023 Jan 3.
Rapid sociocultural shifts in understanding and acceptance of variations in sexual orientation and gender identity have occurred in recent decades, and UK health and social care providers have a legal obligation to address inclusion, discrimination and equality in policies and services. Despite this, lesbian, gay, bisexual and transgender + (LGBT+) people continue to report inadequate health outcomes and suboptimal experiences of care. This article considers the health ecology in relation to those who identify as LGBT+ and outlines the concept of intersectionality. The author discusses some of the issues experienced by LGBT+ people in relation to various physical and mental health conditions and services. The article aims to encourage nurses to consider what steps they can take to improve care for this group.
59Intention Versus Implementation: Diversity, Equity, Inclusion, and Justice Efforts at Your Clinical Practice.PubMed
Bako Orionzi
Pediatr Ann. 2024 Oct;53(10):e354-e357. doi: 10.3928/19382359-20240813-01. Epub 2024 Oct 1.
Diversity, equity, inclusion, and justice (DEIJ) are important factors to be considered in medical education, academic and community health centers, and health care policy. DEIJ efforts have been shown to have a strong influence in advancing health equity, yet these efforts tend to fall on a small group of providers, usually of historically marginalized or minority backgrounds (eg, race and ethnicity, gender identity, sexual orientation, religion). To combat this inequity, more research needs to be done to identify where the burden is falling and what strategies can be set in place to counteract this taxing imbalance. Providers should educate themselves on the anti-DEIJ legislation sweeping across the country, recogniz- ing the misinformation, and advocating for efforts pushing back against this movement. Providers can also advocate for ways their institution or practice can reduce the burden for historically marginalized providers by supporting recognition of DEIJ-related efforts in traditional promotional measures or taking on activities allowing for participation in scholarly work that will advance careers. .
60Rare exemplars and missed opportunities: Intersectionality within current sexual and gender diversity research and scholarship in psychology.PubMed
Lisa Bowleg, Arianne N Malekzadeh, Katarina E AuBuchon, et al.
Curr Opin Psychol. 2023 Feb;49:101511. doi: 10.1016/j.copsyc.2022.101511. Epub 2022 Nov 5.
Using intersectionality as our critical analytical framework, we examined 22 articles on sexual and gender diversity (SGD) published in peer-reviewed psychology journals between January and June 2022 to: (1) identify their engagement with intersectionality's core themes; and (2) highlight key findings and directions for future intersectional SGD research. Our review includes 12 theoretical and empirical articles that addressed a breadth of topics such as intersectional stigma/discrimination, gendered racism, minority stress, and intersectional ableism. This review highlights opportunities within intersectional SGD research in psychology to provide a needed corrective to the discipline's tradition of individualistic, single-axis research focused on predominantly White, cisgender and heterosexual people, and attend to intersectionality's focus on intersecting power relations and commitments to social justice.
61Social-cognitive biases underlying the development of ableism.PubMed
Vikram K Jaswal, Zoe S Robertson
Adv Child Dev Behav. 2024;67:104-131. doi: 10.1016/bs.acdb.2024.07.002. Epub 2024 Jul 22.
Disabled people are the largest minority group in the world. Like members of many minority groups, they face considerable prejudice and discrimination-known as ableism. Ableism reflects entrenched beliefs about what human bodies and minds should be like and a devaluation of individuals who deviate from that ideal. There is surprisingly little psychological science about ableism, and even less about its development. This chapter considers how social-cognitive biases evident in early childhood could contribute to its development. The chapter is structured around four biases: Prescriptive reasoning, promiscuous teleology, psychological essentialism, and the positivity bias. For each bias, we review foundational research about how it manifests in early childhood, speculate about its connection to ableism, and outline avenues for additional research. Understanding how social-cognitive biases contribute to the development of ableism is an important first step in efforts to equip children (and adults) with the tools to reject it.