Here are a couple studies that discuss that issue. For the record, I’m firstborn and gay, but if my brother turns out to be straight, he’s got a Guinness record for gayest straight man coming to him.
Just keep away from the London Underground system, 's all I’m saying.
My joke reply made me think how strange the world would be if anyone could become gay just through encountering certain enviromental factors.
Like walk three times up and down Haight street and you’ll become gay.
It’s more likely that the environment would affect hormonal levels in the mother which would have an effect on fetal brain development.
Also possible, thanks. But still, it’s not a case of the overcrowding causing a child to become gay, it’s the environment perhaps forcing the mother to change the fetus prior to birth.
If the rat study is right, and homosexuality is caused by overcrowding, what’s the solution? Accept it? Spread out? Live in bigger houses or apartments?
Eh, close enough for government work. 
I don’t think you’re going to find many people anymore who say that sexuality is determined after birth…the “homosexuality as a failure of proper psychosexual development” theories aren’t popular anymore. Anybody who tries to say “homosexuality is caused by overcrowding” would be making the argument I made above…not saying that overcrowding of people who are already born would make them gay.
Right, I agree. But several posters here seemed to think that it was impossible for overcrowding to cause homosexuality due to the fact that the sexual preferences were set during early stages of life. Although the second portion of their thesis is correct, the 1st in invalid. I do not know if owercrowding in humans does or does not increase homosexuality, but it is *possible * that it does.
!!! Why does it need a solution?
Anyway, if overcrowding caused homosexuality in humans, I’d expect to see communities like Calcutta with at least somewhat lower birthrates than the norm, and I’m pretty sure that’s not so. Otherwise there’d be fluctuation in dense population centers (lower-breeding generation --> more room --> higher-breeding generation --> etc.). Yes, I know that gay people also have children. I’m talking about the relatively lower rate of breeding that is implied by the animal model (same-sex-directed sexual activity --> lower rat birth rate).
Absolutely. Don’t rabbits just re-sorb their fetuses if conditions aren’t good for giving birth to a litter? Who is to say that humans living in overcrowded conditions doesn’t trigger some kind of mechanism that causes some fetuses to be born with a strong tendency to not make more humans?
To use one of my favorite spin-statements in software development: It’s not a bug. It’s a feature!
What with the (thankfully dwindling) tendancies to view homosexual behavior as a “disease” or “unnatural” or a “sin” or any number of “bad” things…the idea that more folks may catch The Gay thanks to things like the RCC’s views on contraception, or the whole “Go forth and multiply” interpretations of the Bible…why the irony would be downright delicious.
As I no longer live in London, I don’t think I am in any danger of catching Teh Gay.
No, you’re thinking of Castro street. Walk three times up and down Haight street, and you turn into a hippie. The explosive burst of soap and deoderant residue being expelled from your epidermis can cause severe damage to innocent bystanders.
But we pick on you because you smell bad.
Actually, you’ll become a pandhandling teenager.
At first glance, the idea of homosexuality arising as a sort of safety valve feature against overpopulation or overcrowding seems sort of plausible, but how could such a mechanism evolve? - it would seem to select against itself.
Oh ok, fair enough.
Hmm, you raise another interesting point. Maybe I should stick to picking on smelly ol’ rayh and leave this alone.
What about all of the other observable responses to environmental factors in the animal world that have already been discussed? Absorption of fetuses, cannibalism, etc.
If the behavior reduces the risk of “overshoot and crash” population dynamics, it would be selected for but only when the species is confronted with that particular situation.
No, if you were walking up and down Castro street three times, you’d already have to be gay
Haight (or Market might have been a better choice) would cause you to gradualy increase and then decrease your gayness due to proximity to the Castro, that would set up a gay charge in the walker. (A bit like stroking an iron bar with a magnet to induce magnetism).