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Early onset transsexualism in both sexes is usually an extreme form of homosexuality. 90% of early onset male to female transsexuals were gay men before they transitioned, so after transition, they remain attracted to men. ~99% of early onset female to male transsexuals were lesbians before they transitioned. After they transition, they remain attracted to women. Heterosexual early-onset transsexuals are rare, especially among women. In the older literature, early onset male to female transsexuals are referred to as Classic Transsexuals.
Late onset male to female transsexualism is probably related to autogynophilia and is almost certainly not organic. In the older literature, these people are called Fetishistic Transsexuals. Autogynophilia is a paraphilia that is developmental as all paraphilias are. These men are turned on sexually by the image of themselves as a woman. Bruce/Caitlin Jenner is almost certainly this type of transsexual.
However, these men differ from traditional fetishistic transvestites in many ways, as they have cross-dressed more and for longer, and they are much more likely to see themselves as women.
Of late onset male to female or Fetishistic transsexuals, 1/3 are gay, 1/3 are bisexual, and 1/3 are straight. Oddly enough, many late onset male to female transsexuals have been extremely masculine in their lives before they became transsexual.
