There is no, at least none that I can find, actual evidence that anyone is born homosexual. It is not and either or question
Just like some people are born with two heads, a cleft palate, or with both male and female sex organs. It's called a birth defect.
The problem is, that's no excuse for acting on it.
If you are only sexually attracted to small children, you learn not to act on that behavior, or you go to jail.
If you are turned on by burning things, you learn to control what you burn, or you get thrown in jail for arson.
If you are a kleptomaniac you either learn to control your desire to steal or you get thrown in jail or put away in an asylum.
Just because one might be suffering from some sort of mental illness or from a birth defect which predisposes them to be attracted to someone of the opposite sex does not be that they are forced to act on such an impulse.