Heterosexuality is a natural process, for which we have organs to prove but by natural I do not mean that heterosexuality is something that just takes over you by genetic construct . It is a choice in the end but it is not viewed as such because it flows in the natural order of our body. In Afghanistan, one of the highest rated countries where homosexuality is a norm, indicates that homosexuality is a choice. You do not make millions of Afghan men homosexual in a day because their genes acted so, all at once, can you now? There they have boys as collections for their lusts and more so that the more they have, the more respectable they are viewed in that culture.We don't categorize Hetrosexuality as a choice do we?
So you really out to stop making the hetero-homo comparison. The criteria for judging one is not of the other. We know homosexuality fails in reproduction, proof enough that our bodies were not designed for that purpose, or even if someone believes in evolution, well evolution proves you wrong. Your bodies are clear proof of heterosexuality as a natural system, the act of of going homosexual, just proves that heterosexuality is indeed a choice as is homosexuality, on which we must choose to act or not.
By the way, if our sexuality is a genetic process, hard-wired in us, homo or hetero, on which we have no control at all, no choice, then God is simply unfair. Atleast that is what your proposition entails in the end.