Early in this century, neuroanatomists and neurophysiologists began to look for places and functions in the brain that were different in transgender people from non-transgender people. The results of their efforts indicate that there are several structures and mechanisms that are different, some of which can be interpreted.  Finding such differences supports the four factor theory of transgender causation, in that, the theory predicts that genetic gender behavior predispositions exist in the brain and can be detected in its structure and mechanisms.