Sexual differentiation: from genes to gender.

A person's sex can be considered across various levels. To illustrate, genes, hormones, and genitalia can all be considered physical markers of a person's sex. In addition to physical markers, behaviors such as gender role, gender identity and sexual orientation can be perceived as stereotypically male or female. The purpose of this review is to summarize current knowledge of sexual differentiation which emphasizes genetic and hormonal mechanisms that result in male and female development of gonads and genitalia. Finally, consideration is given to associations between genetic sex, gonadal sex, and hormonal sex with gender.