What proof is there that gays are born that way?

I constantly hear this and yes, a very very small percent are born that way, but all of the gays I know and I know a lot were all molested or abused as children, every one. I actually think gays want to believe they were born that way to make themselves feel better about being gay. I would want to think that myself if I were gay. But it does not explain why so many were molested or abused as children does it.