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).