The psychologist John Money used the example of language to demonstrate the misguided nature of such assumptions. You were not born with your native language, and nothing in your “nature” predisposed you to learn English rather than Swahili. Nor did you “choose” English over Swahili. Rather, language was determined by your native culture. Yet our brains are innately predisposed to assimilate a native language, whatever that language turns out to be. Once acquired, it cannot be unacquired—it is as firmly fixed as if we were born with it. Some people have contended that certain environmental influences on sexuality operate in similar ways. As Anne Fausto-Sterling has argued, “bodily experiences are brought into being by our development in particular cultures and historical periods. . . . As we grow and develop, we literally, not just ‘discursively’ (that is, through language and cultural practices), construct our bodies, incorporating experience into our very flesh.”
Research on alcohol use provides a good example of how traits can be biologically influenced and flexible. There is solid evidence that some individuals have a genetic predisposition to excessive alcohol use. Yet genetic influences on complex behaviors are rarely rigid and deterministic, and so situational and environmental variation can modify the expression of such a trait despite its essential components. The psychologists Brian Mustanski and J. Michael Bailey called attention to one notable study showing that the heritability of adolescent alcohol use (that is, the degree to which variation in this behavior was due to genetic versus environmental factors) actually changed as a function of the amount of migration and social mobility in a community. The investigators found that communities with more social mobility and less social control tended to foster the expression of youths’ genetic predispositions to alcohol use. In contrast, communities with more stable social structures and more social control over adolescent behavior had the effect of constraining the expression of young people’s genetic predispositions to drinking. As a result, adolescent drinking was less “genetically determined” in one community than in another. This finding clearly shows not only that genetically influenced traits show significant variation in expression but that the very balance of genetic versus environmental influences is also variable.
– Lisa Diamond, Sexual Fluidity, Loc 370-376