Blanchard did a review recently in which he concluded that there were two types:
1. Pure transsexualism. From a very early age or as far back as they can remember. Biological, developmental disorder.
2. A second type which is simply an extreme form of homosexuality.
I absolutely agree that quite a few of these folks are simply homosexuals. The women want to turn into guys so they can fuck women as a guy, and the guys want to turn into chicks so they can fuck men as a woman. Get it? This type looks more like a mental illness to me. There have been some complete cures with this type which implies that it is not developmental or biological.