So, which is it - nature or nurture? There is no disputing the fact that our sexual physiology and, in all probability, our sexual preferences are determined in the womb. Men and women are different - physiologically and, as a result, also psychologically. Society, through its agents - foremost amongst which are family, peers, and teachers - represses or encourages these genetic propensities. It does so by propagating "gender roles" - gender-specific lists of alleged traits, permissible behavior patterns, and prescriptive morals and norms. Our "gender identity" or "sex role" is shorthand for the way we make use of our natural genotypic-phenotypic endowments in conformity with social-cultural "gender roles". Inevitably as the composition and bias of these lists change, so does the meaning of being "male" or "female". Gender roles are constantly redefined by tectonic shifts in the definition and functioning of basic social units, such as the nuclear family and the workplace. The cross-fertilization of gender-related cultural memes renders "masculinity" and "femininity" fluid concepts. One's sex equals one's bodily equipment, an objective, finite, and, usually, immutable inventory. But our endowments can be put to many uses, in different cognitive and affective contexts, and subject to varying exegetic frameworks. As opposed to "sex" - "gender" is, therefore, a socio-cultural narrative. Both heterosexual and homosexual men ejaculate. Both straight and lesbian women climax. What distinguishes them from each other are subjective introjects of socio-cultural conventions, not objective, immutable "facts". In "The New Gender Wars", published in the November/December 2000 issue of "Psychology Today", Sarah Blustain sums up the "bio-social" model proposed by Mice Eagly, a professor of psychology at Northwestern University and a former student of his, Wendy Wood, now a professor at the Texas A&M University: "Like (the evolutionary psychologists), Eagly and Wood reject social constructionist notions that all gender differences are created by culture. But to the question of where they come from, they answer differently: not our genes but our roles in society. This narrative focuses on how societies respond to the basic biological differences - men's strength and women's reproductive capabilities - and how they encourage men and women to follow certain patterns. 'If you're spending a lot of time nursing your kid', explains Wood, 'then you don't have the opportunity to devote large amounts of time to developing specialized skills and engaging tasks outside of the home.' And, adds Eagly, 'if women are charged with caring for infants, what happens is that women are more nurturing. Societies have to make the adult system work [so] socialization of girls is arranged to give them experience in nurturing.'