Whether or not homosexuality is "innate" is entirely irrelevant to its morality. Even if it was completely a choice (as it is to some extent for bisexual people) it would still be completely okay. Personally I feel like LGBT campaigns do themselves a disservice when they focus on this argument.

Furthermore, if you're going to consider "making assertions without scientific evidence" as sufficient grounds to ban speech, you're going to be silencing a lot of people before you're done.