Social and cultural factors very broadly channel and limit sexual variation in human populations. Sexual laws, codes, and roles do restrict the range and intensity of sexual practices, as far as we can judge from the cross-cultural literature (Herdt and Stoller 1990). Kinsey lent his support to this view; Ford and Beach (1950) documented it in surveys; and Margaret Mead (1961) did so in her ethnographic studies. But biosocial, genetic, and hormonal predispositions also broadly limit and channel. Each culture's theory of the combination of these social and biological contraints we could call its theory of human sexual nature. Yet none of these broad principles, nor the local theory of human sexual nature, entirely explains or predicts a particular person's sexual desires or behaviors. A sexual behavior, that is, does not necessarily indicate an erotic orientation, preference, or desire. The homosexual is not the same as the homoerotic; whether in our society or one very exotic, I will claim, we can distinguish the homosexual from the homoerotic, as Oscar Wilde's case first hinted.
Gilbert Herdt, "Bisexuality and the Causes of Homosexuality: The Case of the Sambia"