[Sex differentiation of central nervous system--brain of man and woman].

[aromatase deficiency]

Sex differentiation of human brain is mostly dependent on the prenatal exposure to androgen (testosterone ). Congenital aromatase deficiency does not disturb male brain development in men . This is quite different from experimental evidence from rodents whose brains need intraneuronal aromatization from androgen to estrogen to induce sex differentiation . There is evidence for male-female differences in brain structures . Some of them (INHA -3 ) appear to be related with sexual orientation . The other (BNST ) might participate in forming gender-identity . In addition , sexually dimorphic features are recognized in some cognitive activities . The possible involvement of genetic factors in human brain sex differentiation is also discussed .