I would not be at all surprised if some of the "sissy boys" we all knew in school turned out to be gay. The slippery slope comes in when we consider how much of our personalities are present from birth, and what do we do with those traits. One may be predisposed from birth to be homosexual, narcissistic, or even violent. That does not make it a good thing that should be nurtured.
I understand finding homosexuality unnatural, but lumping it in with violent behavior is a little much.