Swift-Gallant Ashlyn, Aung Toe, Salia Stephanie, Breedlove S Marc, Puts David
Department of Psychology, Memorial University of Newfoundland and Labrador, St. John's, NL, Canada.
Department of Psychology and Counseling, Immaculata University, Immaculata, PA, United States.
Front Psychol. 2025 Apr 25;16:1559158. doi: 10.3389/fpsyg.2025.1559158. eCollection 2025.
The ratio of the lengths of the 2nd and 4th fingers (2D:4D) is a putative marker for prenatal gonadal hormone signaling and has been linked to human sexual orientation. Although 2D:4D is consistently found to be lower in males than females, the association with sexual orientation is variable across studies, with one meta-analysis finding lower (more masculine) digit ratios in lesbians than heterosexual females, but no overall association in males. However, this previous meta-analysis considered neither unpublished datasets nor bisexual individuals separately from homosexual and heterosexual individuals. Moreover, 17 datasets examining relationships between 2D:4D and sexual orientation have been published since that time, and we located an additional 11 unpublished datasets. We therefore conducted an updated and expanded meta-analysis comprising 51 studies, including 44 male and 34 female datasets, totaling 227,648 participants. This meta-analysis also explored whether 2D:4D differed between heterosexual and bisexual and/or non-exclusive individuals in both sexes. Results indicate lower (more male-typical) digit ratios in homosexual women (right hand 0.26, left hand 0.16; both adjusted following trim-and-fill), and higher (more female-typical) ratios in homosexual men (right hand -0.17, left hand -0.20; both adjusted) compared to heterosexual same-sex counterparts. Moderator analyses do not support publication bias for females. For males, positive findings were more likely to be published, but robustness tests, including trim-and-fill and leave-one-out, support the findings' robustness. No significant differences were observed in 2D:4D between male or female bisexual and heterosexual individuals. These findings are consistent with evidence that prenatal androgens increase attraction to females and/or that prenatal estrogens increase attraction to males.
第二和第四指长度之比（2D:4D）被认为是产前性腺激素信号的一个标志，并与人类性取向有关。尽管一直发现男性的2D:4D比女性低，但不同研究中性取向与该比例的关联存在差异，一项荟萃分析发现女同性恋者的指长比低于异性恋女性（更具男性特征），但男性中未发现总体关联。然而，之前的这项荟萃分析既未考虑未发表的数据集，也未将双性恋个体与同性恋和异性恋个体分开。此外，自那时以来已有17个研究2D:4D与性取向关系的数据集发表，我们还找到了另外11个未发表的数据集。因此，我们进行了一项更新和扩展的荟萃分析，纳入51项研究，包括44个男性和34个女性数据集，共计227,648名参与者。这项荟萃分析还探讨了异性恋与双性恋和/或非排他性个体之间的2D:4D是否存在差异。结果表明，与异性恋同性个体相比，同性恋女性的指长比更低（更具男性典型特征）（右手为0.26，左手为0.16；经修匀和填补调整后），同性恋男性的指长比更高（更具女性典型特征）（右手为-0.17，左手为-0.20；均经调整）。调节因素分析不支持女性存在发表偏倚。对于男性，阳性结果更有可能发表，但包括修匀和填补以及逐一剔除在内的稳健性检验支持研究结果的稳健性。男性或女性双性恋与异性恋个体之间的2D:4D未观察到显著差异。这些发现与产前雄激素增加对女性的吸引力和/或产前雌激素增加对男性的吸引力的证据一致。
