categorization of sexual orientation is not objective or universal; these categories have political implications (Muehlenhard 2000).

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The biologist Anne Fausto-Sterling examined the social nature of biological knowledge about human sexuality. She contends that the act of labeling a person a man or a woman or heterosexual/homosexual is a social decision. Fausto-Sterling acknowledges the importance of scientific knowledge, but considers our beliefs about gender to be the foundation that defines sex and sexual behavior, even affecting the kinds of knowledge scientists produce about sex (Fausto-Sterling 2000).

Synopsis of the book: Sex and the Gender Revolution: Heterosexuality and the Third Gender in Enlightenment London

A revolution in gender relations ocurred in London around 1700 that resulted in a sexual system that endured in many aspects until the sexual revolution of the 1960s. There emerged three genders: men, women and a third gender of adult effeminate sodomites, or homosexuals. This text reconstructs the worlds of 18th-century prostitution, illegitimacy, sexual violence and adultery. In those worlds the majority of men became heterosexuals by avoiding sodomy and sodomite behaviour. Women generally experienced the new male heterosexuality as its victims, but - as prostitutes, seduced servants, remarrying widows and adulterous wives - also pursued passion. The text explores the sexual underworld of extramarital behaviour as central not only to the sexual lives of men and women, but to the very existence of marriage, the family, domesticity and romantic love. London emerges as not only a geographical site but as an actor in its own right, mapping out domains where patriarchy, heterosexuality, domesticity and female resistance take vivid form in our imaginations and senses.

(Synopsis of the book: Sex and the Gender Revolution: Heterosexuality and the Third Gender in Enlightenment London v. 1 (Ch Series on Sexuality, History & Society) by Randolf Trumbach, by Chicago University Press)