Abstract
From the evolutionary point of view homosexual orientation is a puzzle because same-sex sexual preferences significantly reduce individual reproductive success. In this paper, we reconsider two theories explaining human homosexuality as an extreme of an adaptive trait of bisexuality, and as a by-product of another adaptation which consists in a more general shift of males toward feminine characteristics.
In line with these theories, we discuss the issue of male bisexuality, and concept of female fluidity of sexual preferences. Based on the theories, we argue, that opportunistic homosexuality may be adaptive for both men and women within certain social contexts, or in specific periods during individual ontogeny, even if not through direct increase of individual reproductive success.
We propose that same-sex sexuality and/or preferences can appear at specific periods during individual's ontogeny, when samesex alliances would be advantageous for the individual. Based on our arguments, optimal strategy might be an opportunistic one.
Thus, if there is a suitable opportunity, the gender of the sexual partner does not matter when it leads to gaining some benefits (for example resources, territories, or even own reproductive advantages). In other words, if homosexual (as well as heterosexual) behaviour serves a social function for gaining some benefits, or for lowering aggressiveness and clarification of same-sex hierarchy, the activity with the person might be more important than the gender of the person itself.
Thus, motivation for such activities might then be more social rather than sexual.