Sex differences in the structures of human hypothalamus and adjacent brain structures have been observed that seem to be related to gender, to gender problems such as transsexuality, and to sexual orientation, that is, heterosexuality and homosexuality. Although these observations have yet to be confirmed, and their exact functional implications are far from clear, they open up a whole new field of structural-functional relationships in human brain research.
Biomedical Reviews 1997; 7: 17-32.