Beyond that, the idea of "choice" is a dangerous and misleading one. To attribute homosexual orientation, and subsequently, sex, to choice is akin to saying that development of any addiction is a choice. It fails to account for a wealth of empirical knowledge and information about the acquisition of learned responses through instrumental conditioning, imitation, identification, and other powerful processes.
Better to recognize that the constellation of behaviors generally lumped together as "homosexuality" are multiply determined, as are most other complex social behaviors, and to eschew the simplistic binary question of "Genetic--yes or no."
Genetics usually isn’t discussed. The liberal argument is that homosexuals are born that way.
Of course, it helps that media, public school administrators, universities, the legal profession, etc ... are all heavily promoting the “gay lifestyle,” and exposing children to it a ever decreasing ages levels, so to indoctrinate and trap them into the behavior. Sort of along this line: “How do you know your not gay ... There was a time in world history when those individuals who corrupted the youth of a culture were immediately put to death. Hint.