...femininity in boys and homosexuality in men are probably caused by incomplete masculinization of the brain during sexual differentiation. - J. Michael Bailey

In order for a feminine boy to become transsexual, something extra must happen. What is the something extra?

Nobody ever gave Danny Ryan a dress before he asked for one, and he was punished much more than rewarded for his gender nonconformity. If he grows up to be a gay man, as I expect he will, it will be despite the most obvious influences in his social environment, not because of them. In the short term, Danny will receive no more encouragement from others to become gay than he did to wear dresses. Behavior that emerges with no encouragement, and despite opposition, is the sine qua non of innateness. Boys like Danny are poster children for biological influences on gender and sexuality, and this is true whether or not we measure a single biological marker.

Another environmental hypothesis that has received some enthusiasm on the political right is the idea that gay people seduce and recruit. I have never understood how this is plausible. A boy with no interest in homosexual activity wouldn't find it pleasant even if he agreed to it. How is this supposed to turn him gay?