Not really. We use our bodies in many ways that don't conform to some alleged biological function. When people masturbate or have oral sex, they're pretty much disregarding the procreative function of the gonads. When people kiss, what function is being met by the nutrient-seeking mouth? When people lift weights and break down muscle tissue to build more muscle, they're not really using their bodies in any functional way. When marathon runners go thru their brutal training, what function of the body is being met? When I drink wine, I am imbibing a toxic liquid that doesn't really suit the function of my mouth, throat and stomach. Sane people do not live their lives under some strict regimen of only fulfilling their own bodily functions. They creatively define themselves from the inside out--from who they want to be and how they identify and what they take pleasure in. The body simply becomes a tool towards that end.