The prevalence of fa'afafine relatives among Samoan gynephilic men and fa'afafine.

Androphilia refers to sexual attraction to adult males whereas gynephilia refers to sexual attraction to adult females. In Western populations, androphilia in males is familial, but the precise nature of this phenomenon is unclear. Some studies show that androphilic males have preponderances of androphilic male relatives in the maternal, but not paternal, line. In contrast, other studies show that male androphilia clusters in both the maternal and paternal lines. Low fertility populations are susceptible to producing anomalous patterns with respect to biodemographic correlates of male sexual orientation, which may account for discrepancies in the familial patterning of male androphilia across Western studies. We focused on a high fertility population to determine which pattern, if any, prevailed. The prevalence of androphilic male relatives was compared for Samoan gynephilic and androphilic male probands. Samoan androphilic males are known locally as fa'afafine. Compared to Samoan gynephilic males, fa'afafine had significantly more fa'afafine relatives in their maternal and paternal lines. The prevalence of fa'afafine relatives was not significantly different between the paternal and maternal lines for fa'afafine or gynephilic male probands. These findings indicate that male androphilia is familial in Samoa and that it clusters in both the paternal and maternal lines in high fertility populations. We consider our findings in the context of possible explanations for the familial clustering of male androphilia. In addition, we detail how the data presented here illuminate the prevalence of male androphilia in the Samoan population.