In hunter gatherers' culture homosexuals were widely accepted as extra help to support families, according to a study published in the journal Human Nature

Canadian researchers at Centre for Addiction and Mental Health in Toronto and the University of Lethbridge examined 46 ancient transgendered societies (in which homosexual men took transgender role) and 146 non-transgendered societies (in which gay men took the typical male gender role similar to that of females in a society).

The societies were compared on the basis of these factors – population size, socio-political systems, religious beliefs and patterns of residency.

The researchers found that transgendered male androphilia (male sexual attraction to adult males) is an ancestral phenomenon and was accepted by many communities.

"Among transgendered societies, negative societal attitudes toward homosexuality were unlikely. We conclude that the ancestral human sociocultural environment was likely conducive to the expression of the transgendered form of male androphilia," the researchers wrote in their report, named Male Androphilia in the Ancestral Environment.

Societies which accepted homosexuality were those with bilateral descent system of family lineage. In the bilateral descent system, inheritance and descent are passed equally through both parents.

"Our results show that ancestral sociocultural conditions and bilateral and double descent systems were more common in transgendered than in non-transgendered societies. Across the entire sample, descent systems and residence patterns that would presumably facilitate increased access to kin were associated with the presence of ancestral sociocultural conditions," the researchers concluded.