Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada.
PLoS One. 2012;7(4):e36088. doi: 10.1371/journal.pone.0036088. Epub 2012 Apr 27.
Androphilia refers to sexual attraction to adult males, whereas gynephilia refers to sexual attraction to adult females. Male androphilia is an evolutionary paradox. Its development is at least partially influenced by genetic factors, yet male androphiles exhibit lower reproductive output, thus raising the question of how genetic factors underlying its development persist. The sexual antagonism hypothesis posits that the fitness costs associated with genetic factors underlying male androphilia are offset because these same factors lead to elevated reproduction on the part of the female relatives of androphilic males. Western samples drawn from low fertility populations have yielded inconsistent results when testing this hypothesis. Some studies documented elevated reproduction among the matrilineal female kin of androphilic males, whereas others found such effects in the paternal line. Samoa is a high-fertility population in which individuals reproduce closer to their maximum capacities. This study compared the reproductive output of the paternal and maternal line grandmothers, aunts, and uncles of 86 Samoan androphilic males, known locally as fa'afafine, and 86 Samoan gynephilic males. Reproductive output was elevated in the paternal and maternal line grandmothers, but not aunts or uncles, of fa'afafine. These findings are consistent with the sexual antagonism hypothesis and suggest that male androphilia is associated with elevated reproduction among extended relatives in both the maternal and paternal line. Discussion focuses on how this study, in conjunction with the broader literature, informs various models for the evolution of male androphilia via elevated reproduction on the part of female kin.
男性性欲指向成年男性，而女性性欲指向成年女性。男性性欲是一个进化悖论。它的发展至少部分受到遗传因素的影响，但男性性欲者的生殖产出较低，这就提出了一个问题，即支持其发展的遗传因素是如何持续存在的。性拮抗假说认为，与男性性欲相关的遗传因素的适应成本被抵消了，因为这些因素导致了性欲男性的女性亲属的生殖率提高。在测试这一假设时，来自低生育率人群的西方样本得出了不一致的结果。一些研究记录了性欲男性的母系女性亲属的生殖率升高，而另一些研究则在父系中发现了这种效应。萨摩亚是一个高生育率的人群，个体的繁殖能力接近其最大能力。本研究比较了 86 名萨摩亚男性性欲者（当地称为 fa'afafine）和 86 名萨摩亚女性性欲者的父系和母系祖母、姑姑和叔叔的生殖产出。fa'afafine 的父系和母系祖母的生殖产出较高，但姑姑和叔叔的生殖产出没有增加。这些发现与性拮抗假说一致，表明男性性欲与母系和父系的扩展亲属的生殖率提高有关。讨论集中在本研究如何与更广泛的文献相结合，为通过女性亲属的生殖率提高来解释男性性欲的进化提供了各种模型。
