Sexual Differentiation of the Human Brain in Relation to Gender-Identity, Sexual Orientation, and Neuropsychiatric Disorders

Abstract

During the intrauterine period, a testosterone surge in boys masculinizes the fetal brain, whereas the absence of such a surge in girls results in a feminine brain. Since sexual differentiation of the genitals takes place much earlier in intrauterine life than sexual differentiation of the human brain, these two processes can be influenced independently of each other. Gender identity (the conviction of belonging to the male or female gender), sexual orientation (hetero-, homo-, or bisexuality), pedophilia, and the risks for neuropsychiatric disorders are programmed into our brain during early development. There is no proof that postnatal social environment has any crucial effect on 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 changes in the supply of sex hormones on the one hand and sex differences in behavior in health and disease on the other.

Abbreviation

AR

Androgen receptor

BSTc

Central nucleus of the human bed nucleus of the stria terminalis

DES

Diethylstilbestrol

CAIS

Complete androgen insensitivity syndrome

CAH

Congenital adrenal hyperplasia

ER

Estrogen receptor

FtM

Female-to-male transsexual person

InM

Intermediate nucleus

INAH

Interstitial nucleus of the anterior hypothalamus

MtF

Male-to-female transsexual person

SCN

Suprachiasmatic nucleus

SDN-POA

Sexually dimorphic nucleus of the preoptic area

SON

Supraoptic nucleus

Notes

Acknowledgments

We thank Mrs. W.T.P. Verweij for correcting the English. Dr. A-M Bao is supported by Nature Science Foundation of China (30970928), Science Foundation of Chinese University, and China Exchange Programme of the Royal Netherlands Academy of Arts and Sciences (KNAW) (project 09CDP011).

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Copyright information

© Springer Science+Business Media, LLC 2013

Authors and Affiliations

  1. 1.Netherlands Institute for NeuroscienceAmsterdamThe Netherlands
  2. 2.Department of NeurobiologyZhejiang University School of Medicine, Key Laboratory of Medical Neurobiology of Ministry of Health of ChinaZhejiang, HangzhouChina

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