The question implies a reversion of self-identified sexuality… In that case, the other answers here are great…
I do wonder, though, at the earlier end of the spectrum, when self identity is not firmly explored or established… It does seem possible that, if everyone were both instructed in a heteronormative fashion, and provided with ample lifetime sexual partners of generally acknowledged attractiveness (not asking for much, are we?), that homosexual self-identification would surface much later in life as some kind of statistical average. Given that scenario, it's also possible that if such homosexuality were treated with open hostility uniformly throughout society, that many would never come out – which makes them scientifically invisible even if there really is a genetic link in the mix somewhere, but no less real.
Sounds like a sexual welfare state run by the 700 Club. Ew!
Also, as the unfortunate Anon sarcastically un-mentions, "that's not how human sexuality works".
Chuck the rest, and leave in the unlimited supply of desirable sex partners of whatever orientation? Now you're talking… Though, that could also look a lot like "boring", or at very least "conscientious globally-legalized prostitution".
deano.com 