This is correct, but you're going to get a lot of people on Holla Forums who insist that this is nothing more than "prison gay" behaviour from animals with no access to the opposite sex. Of course, animals DO display "prison gay" homosexual behaviour when the opposite sex isn't available…but a few species (sheep most notably) ALSO have members that are preferentially homosexual. Theories of the etiology of homosexuality need to either take that into account…or explain how homosexuality in humans is completely different.
Essentially every theory is garbage, for one reason or another:
Twin studies disprove it's strongly genetic. At best, genes might be involved in a susceptibility to developing homosexuality. (Kinda like schizophrenia.)
The rate of childhood abuse amongst gays is nowhere NEAR high enough. Not to mention here people assuming the direction of causation: studies on child molesters have shown that they tend to specifically target socially ostracized children. Being GNC ("gender non-conforming") in childhood has a strong association with adult homosexuality, and queers who report having been GNC children are the most likely to also report having been molested. It may be more that being an obviously gay kid (and rejected by other kids for it) is a risk factor for molestation…and not that molestation causes homosexuality.
Also, this:
…is incorrect, most victims do NOT become pedophiles.
Same problems as above: the "absent father" dynamic isn't common ENOUGH to come close to being an explanation. And again, proposing it does could be confusing the direction of causation. That's especially true of shit like family dynamics where research is highly vulnerable to bias and misinterpretation.
This one is really interesting. Greg Cochran has argued before that the fitness cost of homosexuality is way too high for it to be genetic, and that it's probably caused by a pathogen that passed from sheep to people with the rise of agriculture. But he's suggested it's a pathogen we haven't even DISCOVERED yet. So he's got nothing much.
Re: t. gondii, people have already pointed out some holes (e.g. owning cats has a poor correlation with actual rates of homosexuality), and some of the "evidence" anons are coming up with is a serious stretch, e.g.
…which is basically a meme fetish, doesn't really exist much outside of the internet:
guilfordjournals.com/doi/abs/10.1521/aeap.2006.18.6.490
Even amongst guys who call themselves "bugchasers" online, only 7.5% of the sample these researchers looked at were even serious enough about it to deliberately seek HIV+ partners. For most people, it's a super-risky masochist fantasy. Kind of like the guy who jacks off to sending a dominatrix all his banking information because he gets off to the idea that she could steal all his money and ruin him. Most guys aren't dumb enough to really do this.
Rare in general.
Ages ago, I was trying to find studies on the actual prevalence of homosexuals who have anal sex. I found one study that said 80%+ currently claim to have it, but that was up from single-digit percentages from several decades ago. Of course, some of the men in the earlier studies may have been lying, but the gap was still enormous, it was like a 10x increase.
Also, heterosexuals engaging in anal sex is now up to 36% (for women) and 44% (for men), up from practically zero.
I blame pornography.
Anyway, the last theory I can think of is:
Which seems to have a fair amount of evidence behind it. But basically all the specifics are unknown: WHY would there be a hormonal imbalance in the first place, what causes it, etc.
If the prevalence of homosexuality was ACTUALLY rising, that might be a clue. But…though Holla Forums acts like it is, it's not. Homosexuals have been single-digit percentages of the population since researchers started trying to track sexual preferences.
Additionally, most theories of etiology only apply to MALE homosexuality and not FEMALE homosexuality (which may be caused by something different anyway).
Bottom line, the cause of homosexuality is still a mystery. Whatever your pet theory is, it's just that. It might as well be voodoo.