This whole genetic reason for being gay is a lie easily disproven.
I can choose to have sex with either a man or a woman. If I do it with a man, that means I'm gay. If I do it with a woman, that means I'm straight. If I do it with both, that means I'm bisexual.
Guess what you prevaricating, dishonest, disreputable, rainbow badgers, I know it it's a choice. And I know which choice you made.