"The kin selection hypothesis posits that male androphilia evolved because androphilic males invest more in kin, thereby enhancing inclusive fitness." However, increased kin-directed altruism has only been seen in societies that exhibit transgendered male androphilia. To test the validity of the kin selection hypothesis for male androphilia, the authors examine the relationship between ancestral sociocultural conditions, access to kin, and societal reactions to homosexuality and the expression of male androphilia as transgendered or non-transgendered. They find that ancestral sociocultural conditions and bilateral and double descent systems were more common in transgendered than non-transgendered societies.