Transgendered androphilic males were accepted in traditional hunter-gatherer cultures because they were an extra set of hands to support their families. Conversely, by investing in and supporting their kin, these males ensured that their familial line -- and therefore also their own genetic make-up -- passed on to future generations despite their not having children of their own. This is according to an ethnographic study led by Doug VanderLaan of the Centre for Addiction and Mental Health in Canada, published in Springer's journal Human Nature. The study reports that this "kin selection" is still at play in pro-transgender societies today.

'Androphilia' refers to a predominant sexual attraction towards adult males, and takes on one of two possible gender roles depending on the cultural context: sex-gender congruent male androphilia (the typical male gender role) or transgendered androphilia (a gender role markedly similar to that of females in a given culture). Typically one of these variations is dominant within a society. For example, sex-gender congruency is more common in Western cultures, whereas the transgendered form is more typical of non-Western cultures, such as that of the Polynesian island nation of Samoa. The researchers also wanted to test predictions that enhanced kin-directed altruism is prominent in societies in which transgendered male androphilia is predominant.

To answer this question, VanderLaan and his colleagues compared the sociocultural environment of contemporary transgendered societies with ancestral small-group hunter-gatherers. Ancestral group size, sociopolitical systems, religious beliefs and patterns of residency were analyzed in 146 non-transgendered societies, and 46 transgender societies.

The analysis utilized ethnographic information about well-described nonindustrial societies from the Standard Cross-Cultural Sample.VanderLaan and his colleagues found that transgendered male androphilia is an ancestral phenomenon typically found in communities with certain ancestral sociocultural conditions, such as "bilateral descent." This term refers to societies in which the families of both one's father and mother are equally important for emotional, social, spiritual and political support, as well as the transfer of property or wealth.

Also, the acceptance and tolerance of same-sex behavior evolved within a suitable, accepting environment in which discrimination against transgendered males was rare. Importantly, kin selection might have played a vital part in maintaining genes for male androphilia these societies. For example, it continues to be a driving force in contemporary Samoan fa'afafine transgender communities.Unless transgendered androphilic males are accepted by their families, the opportunities for them to invest in kin are likely limited. What was true of our ancestors still holds true. A society's specific social organization and its general acceptance of transgenderism and homosexuality is even important today. When supported by society, transgendered males invest their time and energy in their kin in turn.