Kirkpatrick RC, Lévi-Strauss C
Curr Anthropol. 2000 Jun;999(2):000385-000413.
Homosexuality presents a paradox for evolutionists who explore the adaptedness of human behavior. If adaptedness is measured by reproductive success and if homosexual behavior is nonreproductive, how has it come about? Three adaptationist hypotheses are reviewed here and compared with the anthropological literature. There is little evidence that lineages gain reproductive advantage through offspring care provided by homosexual members. Therefore, there is little support for the hypothesis that homosexuality evolved by kin selection. Parents at times control children's reproductive decisions and at times encourage children in homosexual behavior. There is therefore more support for the hypothesis of parental manipulation. Support is strongest, however, for the hypothesis that homosexual behavior comes from individual selection for reciprocal altruism. Same-sex alliances have reproductive advantages, and sexual behavior at times maintains these alliances. Nonhuman primates, including the apes, use homosexual behavior in same-sex alliances, and such alliances appear to have been key in the expanded distribution of human ancestors during the Pleistocene. Homosexual emotion and behavior are, in part, emergent qualities of the human propensity for same-sex affiliation. Adaptationist explanations do not fully explain sexual behavior in humans, however; social and historical factors also play strong roles.
对于探索人类行为适应性的进化论者来说，同性恋是一个悖论。如果适应性是以生殖成功来衡量，而同性恋行为不具有生殖性，那么它是如何产生的呢？这里回顾了三种适应性假说，并与人类学文献进行了比较。几乎没有证据表明家族通过同性恋成员提供的后代照料获得生殖优势。因此，同性恋通过亲缘选择进化而来的假说几乎没有得到支持。父母有时会控制孩子的生殖决策，有时会鼓励孩子进行同性恋行为。因此，父母操纵假说得到了更多支持。然而，对于同性恋行为源于对互惠利他主义的个体选择这一假说的支持最为有力。同性联盟具有生殖优势，性行为有时会维持这些联盟。包括猿类在内的非人类灵长类动物在同性联盟中使用同性恋行为，而这种联盟在更新世人类祖先分布的扩大中似乎起到了关键作用。同性恋情感和行为部分是人类同性归属倾向的衍生特质。然而，适应性解释并不能完全解释人类的性行为；社会和历史因素也起着重要作用。
