Joe Quirk

http://www.sfgate.com/cgi-bin/blogs/jquirk/detail??blogid=146&entry_id=48335

Your hypothalamus is in charge of horniness. Next time you get aroused, blame your hypothalamus. A tiny part inside the hypothalamus is called the BST nucleus. If you're a male, this source of your male sexuality is about the size of a grain of rice. If you're female, it's about 30% smaller. Females are short-grain. Males are long-grain. That's what makes us men.

Professor D.F. Sweeb dissected the brains of male-to-female transsexuals and found that male transsexuals have a female-sized BST nucleus. Male transsexuals have a female structure in their brains in charge of gender identity.

Female brain, male body.