The “female fertility–social stratification–hypergyny” hypothesis of male homosexual preference: factual, conceptual and methodological errors in Barthes et al. [Commentary]

Barthes, Godelle, and Raymond (2013, Evolution and Human Behavior, 34, 155–163) proposed a hypothesis to (1) identify the process by which genes influencing male homosexual preference (MHP) are passed on over evolutionary time, and (2) account for why life-course persistent MHP is restricted to humans. According to their hypothesis, certain genes lower reproductive success in male carriers by causing MHP, but these same genes promote fertility in female carriers (i.e., sexual antagonism). Barthes et al. proposed that the female carriers of genes for MHP have physical cues of fertility (i.e., beauty) that help them marry up the social class hierarchy (i.e., hypergyny). In doing so, these females experience increased access to resources, which allows them to increase reproduction further thereby compensating for the low fertility of their homosexual male relatives. To evaluate their hypothesis, Barthes et al. developed a mathematical model to determine whether their hypothesis was theoretically feasible. They also performed an ethnological analysis to assess whether MHP was more commonly found in societies with greater social stratification. Our criticisms of Barthes et al.’s article extend to many of the key conceptual and methodological aspects as well as much of the factual information