Human Sexuality question

I remember reading an article somewhere that said that when the population of a group of mammals, including humans, becomes dangerously high and concentrated the sex drive of the females in that species dwindles. It’s kind of a natural population control mechanism, apparently.

I recently got into a debate on another board about the evolutionary benefits of homosexuality and I’d like to cite that article to bolster my argument. Problem is, I can’t find it. Have any of the teeming millions come across anything similar and if so, can you please provide me with a link to it? I would be eternally grateful and would gladly reciprocate with copious amounts of beer/wine/poison of choice should we ever meet at a dopefest.


I’ve never heard anything to support this claim, but God knows I’ve heard arguments claiming queerness is a form of population control. Makes no sense. No matter how high the population may be, you have a greater likelihood of passing on your genes if you have babies than if you don’t. The only way around this would be if being gay provided some enormous benefit to ones immediate family, and to no one else - not the other tribe members, and certainly not to humanity as a whole. Otherwise, whatever genetic trait that existed to link overpopulation and homosexuality would be bred out as soon as overpopulation struck.

I guess most people don’t understand evolution real well. Evolution is not a magical process that exists to benefit a species. It’s the success of certain traits at the expense of other traits. If a trait makes you less likely to breed, it’s gonna leave the population.

I don’t recall ever hearing that there was some required large threshold for evolution – that a trait had to be of “enormous” benefit. Seems like a mutation with even a very minor benefit would have quite an effect when applied over thousands of generations.

This is the only thing I could find using the online database searches in biology, anthropology, sociology and psychology:

Title: The population explosion and the status of the homosexual in society.
Author(s): Loraine, John A., Chew, Iain, Dyer, Tim
Source: Understanding homosexuality: Its biological and psychological bases. Loraine, J. A. (Ed) Oxford, England: American Elsevier, 1974. 217 pp.
Classification: Social Processes & Social Issues (2900)

The article didn’t seem to directly address your arguments. The abstract talked a lot about drugs and changing of social norms. Plus, the publishing date is pretty old in terms of positive regard in academic circles for homosexuality.

While I imagine you are right about mammals not wanting sex, I doubt that changes sexual orientation. I would posit that food supply, crowding and possibilities of incest pregnancies might have more to do with low pregnancy rates than sudden changes in sexual orientation.

I wouldn’t discount the possibility that it’s an adaptation that gets passed down.

Consider longevity. One theory as to why we live to be 90, 100, 110, etc., instead of dying off shortly after our peak reproductive years, is that the likelihood of your distant ancestor, personally, surviving long enough to reproduce was higher if she had living grandparents who helped her parents with the child care and in other ways. And if she had such grandparents, chances are decently good that she inherited the longevity genes from them, via her parents.

This, despite the fact that there’s no direct process weeding out those with shorter lifespans and then passing on the genes of the survivors.

In the case of being attracted to the same gender, suppose there’s a gene for it, perhaps a recessive gene or perhaps a gene that only codes that way in conjunction with some other genes lining up a certain way and under other circumstances is dormant. Now suppose that the likelihood of your distant ancestor surviving long enough to reproduce is higher if you’ve got a gay aunt or uncle who don’t have kids of their own and who pitch in with the child care and in other ways?

I think it’s fair to say that it’s unlikely that there’s a single, dominant gene for homosexuality, which if I recall my Mendelian rules would indeed be selected against my natural selection (assuming gay folks are significantly less likely to have straight sex and therefore reproduce), but in the above-described scenario it can selected for, in the same kind of indirect way as the selection for longevity.

Just a note: Spamming the local enviornment is not necessarily the most succesful reproduction strategy. Example: Take two tribes of people. Assume that one of these tribes has 10% of its population as non-breeders. Now, this population will grow at 90% of the other, but there will be many more additional adults to help with child-rearing and such. If conditions are such that it is more advantageous for the population as a whole to have a certain percentage of itself not reproduce, it makes sense that you’d get various stabilizing factors producing people with no interest in having children themselves.

Either I was unclear, or you misunderstand me. For a gene to be passed on whose primary effect is to prevent its possessor’s reproduction, the benefit to nearby family members would have to be extremely strong. You know, to compensate for the fact that presumably the gay cavepeople didn’t mate. (Even the gay caveperson’s nieces and nephews, though, only share an eigth of their genes.)

The gene would never disseminate throughout a group (except a small one, and even then only through extraordinary chance) in order to have the effects you guys are imagining. It wouldn’t make it that far because it (most likely) stops its possessors from reproducing! In the hypothetical tribal environment, why would Gay Ogg’s gayness be of such strong benefit to his family, and so little benefit to un-related members of the tribe?

Declaring that a group in which the whole tribe had the gene is sorta cheating - because it’s simply unlikely it would spread through the whole group. You have to look first at the effects on the individual organism, THEN at broader social effects. Because what happens on the individual organism level is far more important.

I guess I still don’t understand you.

I don’t see that a suggested ‘gene for homosexuality’ would necessarily “prevent reporduction”. Many gay & lesbian people throughout history have produced children (even Oscar Wilde, for example). And many of the g/l couple I know currently are raising children; I’ve even seen stories about “the gayby boom” in the media.

Two possibilities in which homosexuality could be entirely plausible as a genetic trait (even supposing that the homosexuals ourselves never produced children):

  1. Homosexuality as a recessive trait. Arguendo, let’s take the very simplest case – imagine homosexuality was determined by a simple recessive gene, such that if you had the gene HH, you would be homosexual, but if you had hh, Hh, or hH, you wouldn’t be. That would mean, if I am HH, both my parents are carriers of one H, and my brother possibly would be too. If my hanging around made it more likely that he would successfully pass on his genes, that means that I’ve helped him pass on H. If one of his H-bearing progeny meets another H-bearer and has a kid who ends up with HH – presto, I’ve helped pass the gay gene along, via my straight little brother.

  2. I read somewhere that there was some evidence that genotypes associated with homosexuality was located on a very quickly mutating bit of genome. If that were the case, it wouldn’t matter whether or not gay people failed to reproduce - we’d just keep popping up.