BT - the first link is a very interesting article excerpt:

New findings about the genetic and other factors that influence the brain's sexual development could do more than simply rewrite the textbooks. They might provide insights into conditions such as transsexualism — and perhaps eventually lead to tests that could determine whether a baby with an intersex condition is more likely to grow up thinking, feeling and behaving like a man or a woman.

the second link is also interesting:

They found that people who speak two languages have more gray matter in the language region of the brain. The earlier they learned the language, the larger the gray area.