title: Sexual differentiation of the human brain: relation to gender identity, sexual orientation and neuropsychiatric disorders.
abstract: During the intrauterine period a testosterone surge masculinizes the fetal brain, whereas the absence of such a surge results in a feminine brain. As sexual differentiation of the brain takes place at a much later stage in development than sexual differentiation of the genitals, these two processes can be influenced independently of each other. Sex differences in cognition, gender identity (an individual's perception of their own sexual identity), sexual orientation (heterosexuality, homosexuality or bisexuality), and the risks of developing neuropsychiatric disorders are programmed into our brain during early development. There is no evidence that one's postnatal social environment plays a crucial role in gender identity or sexual orientation. We discuss the relationships between structural and functional sex differences of various brain areas and the way they change along with any changes in the supply of sex hormones on the one hand and sex differences in behavior in health and disease on the other.
authors.affiliation: Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China. baoaimin@zju.edu.cn
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Bao
authors.forename: Dick F
authors.initials: DF
authors.lastname: Swaab
mesh_terms: D001921:Brain / Q000254:growth & development* / Q000502:physiology; D005783:Gender Identity; D012739:Gonadal Steroid Hormones / Q000502:physiology; D006801:Humans; D001523:Mental Disorders / Q000209:etiology; D009422:Nervous System Diseases / Q000209:etiology; D010988:Play and Playthings; D012733:Sex Differentiation; D012725:Sexual Behavior / Q000523:psychology*; D013739:Testosterone / Q000502:physiology; D014189:Transsexualism / Q000209:etiology
chemical_list: D012739:Gonadal Steroid Hormones; D013739:Testosterone