Funny and informative, and I loved it to death--especially that last past.

On the finger ratio thingy, I'm a woman whose left hand has a longer ring finger and my (dominant) right hand has ring finger and index finger of almost the exact same length, with the ring finger being only slightly longer. I thought that was interesting, because I don't generally orient myself in any specific way.

Hmm, I was pondering the kin altruism theory vi-a-vis homosexual women. It makes sense to have extra, childfree women around to help support widows (all those sabre tooth tigers...) and their young children. However, as a lesbian mother myself my experience is that, to a woman, my romantic partners have been far more self-absorbed than heterosexual women of similar age and circumstances and jealous of my attention to my children.

It could be that, as a mother, I've simply attracted those women (and, it has to be said, men) who are needful of mothering. Or it could be that homosexual women are generally emotionally under-developed.

There seems to be a theory you left out, and I would like your input on it. It is that homosexuality is a spectrum problem(in the sense it hinders reproductive success, not morally wrong or anything like that.) That in certain situations and environments having a more effeminate brain leads to reproductive success. Hispanic men who are know as being Latin lovers have a higher rate of homosexuality. It could be that a more effeminate brain increased reproductive success and homosexuality is just too far along the spectrum. Evolution didn't select out homosexuality because most of the time it increased chances of reproduction, and the few outliers were a reasonable cost. This would also explain homophobia. If for instance you are a member of a family who has brain feminizing genes (aroused by men just like the aggressive homophobes you spoke about earlier) then enforcing heterosexuality allows someone to reap the benefits of the feminine brain without paying the evolutionary cost because his relatives will be forced to have heterosexual sex and spread their(and his homophobic relatives) genes.

Hello Dr. Jesse,

Your post was very interesting to read, especialy the "sneaky f*cker theory". Thanks for share this informations. I'm very curious about it and I'll be wait for the next posts. Have a nice day.

Hmmm...how did I know you weren't going to address the chunky girl baby theory?

...but you have some very good points. It is disheartening the way the moral police have made "objectivity" a bad word. Certainly there must be patterns.
I'm not agreeing with you, but the path towards excepting being "GAY", is by understanding what it is and what can't be defined as well. I treat "GAY" people different then "straight" people... and I am tired of being told that this is wrong, because it works for me and it works for the people I know. There are benefits to being gay. It is time we recognized this and stopped looking down on them. It's nice to have a higher disposable income now isn't it Sneaky F*cker? Don't tell me life is a burden, because your doing just fine.

...and fag hag ladies? shut the fuck up. you know he gets away with murder.

I don't understand why there needs to be evolutionary benefits to being gay. It seems like that would be an assumption stemming from thinking that being gay has natural benefits.

To me, it makes perfect sense that people who are gay are just not selectively advantageous - end of story. Gays don't make kids, they lose in the eyes of nature. Honestly, this isn't rocket science. There are reasons why being gay would make a person happier (one being they wouldn't have to deal with the negative emotions needed to understand and tolerate the opposite sex), which is totally different than being selectively advantageous. In a perfect world, I'd understand exactly what was going on in a girls head, but truth is I have to take the time to tolerate differences of thought... caused by real neurobiological differences. This definitely beats down on my happiness when I'm not horny. I take the time to do this because it's important to me that I follow the advice put forth by my natural mechanisms. If it's not important to you to follow your natural mechanisms, you don't have to deal with this... but you'll theoretically not have any offspring, and lose in nature.

Why does every behavior need to have potential to be selectively advantageous? Bluntly, some behavior that is seen on our world will lose, and that behavior is not successful in the eyes of nature.

Thanks for an interesting read! I've linked to you from my blog GenderPop (http://www.gender-pop.com).

The counter arguments to kin altruism theory don't seem so strong. No matter that a gay person's resources would be funneled to his/her partner, since it is also true the other way around and neither of the two need to sustain children, sureley some resources would remain to be shared with relatives. Also, perhaps our cave-dwelling ancestors were not homophobic at all? Hence a gay person and his family may have been perfectly endeared to each other?
Also, isn't there some theory out there suggesting that a genetic trait in a female causing her to be more fertile - become pregnant more often - could have as a side effect that some of her children turn out gay?

Thanks for a very helpful post, and some really interesting and insightful comments.

Until this post (linked through Andrew Sullivan), I never really had an alternative to the idea that being gay was an evolutionary "flaw." As Gillian put it, "gayness does not seem to be naturally beneficial because it doesn't lend to producing offspring" and so I haven't been able to get past the idea of homosexuality as an evolutionary dead-end.

This is not a value judgment, but as a straight male, it is embarrassing nonetheless because it seems to lead down the path of linking gayness with other disorders that are more clearly "flawed," such as, to name an extreme, Down Syndrome. That is: straight is normal, and gay is not. I don't like the idea of thinking that straight is normal and gay is other, but I haven't able to quite shake it.

Not that it much matters really, people are people, and the whole beauty of a diverse society (or at least this one) is that what is "normal" is kind of a silly argument on its face. I have gay friends and colleagues, and I hope I treat them the same as my straight friends and colleagues, and the same for strangers. But still, but still, this nagging feeling, this guilt for some feeling of implied superiority I don't want to own.

Quite frankly, it never crossed my mind, idiot that I clearly am, that there might be some form of evolutionary advantage or reproductive advantage to being gay. It just started and ended w/ the obvious fact that two gay individuals can't reproduce. But the "sneaky fucker" theory adds a wrinkle, as might the idea that, perhaps, there are situations in which certain behavioral characteristics associated with being gay (such as, maybe, male effemininity, female masculinity) can be advantageous in certain situations or societies. Just now, I find myself wondering about my lesbian friend who's an ex-Marine: might it be the case that, sometime a long time ago, more masculine women were more likely to survive in a time of war?

Who knows? To me, it doesn't matter. The idea that there might be evolutionary advantages to being gay, regardless of what they are, mean that being gay is "normal." And not not-normal. It pulls gayness out of the realm of mental illness and genetic disorders and means that it's just another way to survive.

In an amusing tangent, see how the smaller examples of cuttle fish have evolved to sneakily spread their seed:

http://www.pbs.org/wgbh/nova/camo/mating.html

Despite their appellation ("flamboyant cuttlefish"), it is not apparent that there is such a thing as a gay fish.

Incredibly interesting stuff, but I as an assuredly gay man, I am a bit unnerved that my ring finger is longer than my index.
I do have a question though, predicated on the assumption that homosexuality has a genetic basis. In the historical past, homosexual males and females were encouraged through extremely strong social pressures to mate with the opposite sex and reproduce, thus passing on the homosexual attraction material to younger generations. Now that these strong social pressures are arguably diminishing in many parts of the world, and therefore less gay people are reproducing in the traditional sense, does this mean that gay liberation might have the perverse effect of actually lessening the numbers of gay people? (I know I am ignoring the fact that 'liberated' gay people do in fact reproduce in ways that do pass on their genetic material--i.e. artificial insemination, etc--but I think that it could be demonstrated that these numbers are no hugely significant.)I'm no evolutionary psychologist, but this has puzzled me for a while, so I'd love to hear an expert's perspective.

I know this doesn't add much to the discussion, but one of my favorite Paul Lynde zingers from the Hollywood Squares went something like this:

Peter Marshall: Paul, according to Shakespeare, "Virtue makes a woman radiant, and temperance makes her most admired, but THIS makes her most beautiful of all." What is it?

Paul: A fifth of vodka.

Btw.....if one of the prime effects and/or goals of natural selection is variegation, doesn't that somehow in itself make homosexuality not a surprise? That is to say, if the variety that cross-breeding produces a spectrum, why wouldn't red and purple be part of the spectrum? Just curious.

That makes sense, in terms of reproduction, in that historically lesbians probably never had that much control over their reproductive destiny - especially if they were married off when young.

For gay males, who had control that the lesbians lacked, opting out of sex with women was an option (even if marriage couldn't be avoided). But even then, they no doubt saw the advantages and necessities of biting the bullet and having children, in order to preserve an estate, or obtain extra hands for labor.

"(This one doesn't quite gel, especially when you consider that a gay person's resources are usually funneled to their same-sex partners. Also, for most people, being gay doesn't exactly endear you to your relatives.)" Surely there are -- or were -- enough cultures in which homosexuality is/was not looked down upon that one can examine the patterns of associations that form when puritan moralists aren't in charge. And how about other primate species? Human biology was set long before our ancestors made up religion. Might this theory "gel" in a pre-gel culture? If Og fell for Trog, who's to say he didn't join Trog's band and provide twice as much support for Trog's little nieces and nephews?

There is considerable eveidence to indicate that gay males are over represented in groups possessing "artistic talents" (i.e. actors, costumers, set decorators, ballet dancers, etc. etc.) and that these natural talents provided the basis of shamanistic performances in ancestral populations. In these groups religion and theatre were one and the same. Transgendered males were often the most powerful shamans and their families DNA benefited from them being such. The gay males families replicated his genes along with their own and kept the talent and sexual orientation in the pool. Shamanic religion was the primordal religion and those groups with a powerful shaman were more productive and reproductive. Shamanism held the group together.

I had a thought with regard to the evolutionary viability of homosexuality.

I'm not 100% on my cave-person behaviour here. But, consider a cave-lady who has had four or five sons in a row, the fifth son being gay. I would imagine that some of her older sons may have been killed hunting, moved to another tribe or started their own tribe.

It seems a reasonable theory to say that in a cave-person society that the women stay close to the same tribe and the men venture off. (I think that perhaps the wife snatching thing came a bit later. Correct me if I'm wrong) Anyway for the sake of my argument, I am supposing that the rest of her sons are a bit scarce.

Presumably the sons that have left the tribe have done so due to tribal hierarchy, there is no place for them there as there is already a strong alpha male with a sytem of subordinates. So a tribe containing many breeding males.

In this situation would it be advantageous for the mother to have this fifth and youngest son stay with the tribe? If he is effeminate enough, the heterosexual males in the tribe will not find him a threat and he could be socially grouped in with the women.

The women then have a comrade who isn't a threat to them, as he doesn't want to dominate or reproduce with them, and his superior physical strength is an asset in terms of protecting them when the other men are away, or even protecting them from the unwanted advances of the other men.

Perhaps a cave-woman who has already had 5 children, is not in very good physical shape and not only needs physical protection from predators but from further pregancies which would be detrimental to her health.

Perhaps gay offspring served as the stay at home body guards. Protecting the wellbeing of older tribe members is advantageous as you are also protecting the collective knowledge of the tribe which is mainly held by the older members.

Great post, Jesse - I'm a clinical psychologist that mostly works in the area of HIV risk reduction (don't bother checking the library, I'm barely out of school and just transitioned from a heavily clinical path to a research job) - I'm familiar with almost every study you discussed, but had never heard of research linking the digit-length research with sexual role preference - do you happen to have a citation for that you could share?

Thanks!

....if there is a genetic component then it could be that gay men are simply a by-product of a more advantageous genetic signature for female fertility.

First (1), there is that Italian study (sorry no links, in a hurry) that the female relatives (mothers, sisters, aunts) of gay men are more fertile than that of heterosexual men. Second (2), I'll throw in a personal observation that in the families of gay men there may be a tendency for the birth of females by ratios of as much as 4-1 (or more!). Thus fertility increases by simple numbers and by increasing the number of females over males (ie. more wombs, polygamy anyone?). Third (3), there is a study published by UCLA and also further ongoing at UCLA and perhaps also Illinois (or was it Chicago, Northwestern?) which showed that mothers (and sisters) of gay men had a skew towards an unmethylated X-chromosome (one that refused to shut down). This did not cause any harm in terms of any genetic disorder, it may mean that a strong X-chromosome may be the cause of a same-gendered orientation by expression of genes normally meant to determine feminine characteristics.

And so.... a possibility exists that the genetics of my #3 may be responsible for the increased fertility of #1 perhaps by a preponderance for producing female offspring (my #2) and thus simply produces gay men as a by-product. Thus on an evolutionary basis, gay men are a sign of increased fertility in a population, but have nothing to do with it. Although if the strong X-chromosome idea is correct, a gay man would pass it along to his daughters, thus insuring that more gay men would possibly be born after skipping a generation.

I wondered why?
Shockingly sneaky female social worker! Her shocks too my breath away.
You have solved my questions.
Thanks...

An often mistaken for capable woman who has a penchant for men!
Thanks,
again.

I like this article but would like some clarification. Is the term "homophobic" not some what incorrect? Are people physically affraid of gay people? I think not. People are affraid of being ASSOCIATED with gay people, mainly because others may think they are gay themselves. These people may need some time for self reflection in their lives.

I also feel like sexuality is something that evolves over time, in the same way that people evolve into themselves over time. Individual sexuality is subject to change. Many people experience different orientations throughout their life time. I dont think there is a blanket reason for homosexuality/bisexuality. I find it some what ignorant that anyone would think that there is just one reason. My real question is what difference does it make anyway? And why are people researching it? Are people thinking that if we find a reason for it that it could be "corrected"? I know that sounds like paranoia, but why else would anyone fund the research? Does anyone know who IS funding this research??

I am without a doubt gay because of how many older brothers I have and I am right handed. However when I was younger I had many failed relationships with girls as I was begining to become sexually aware, but as I continued to develop I no longer had any sexual attraction to girls. I was wondering if my failed relationships could of led me to be more fond of men sexually? We know that being homosexual isn't linked to a specific gene because of twins that one is gay and the other is straight and there is a correlation between how much birth control a mother takes to if a son is gay. The less birth control the more likely he is gay. What item is in birth control that would also be naturally be effecting a womens womb while the baby is developing. What item X lacks or becomes more immune that effects all of the people who become gay. I would believe there is one overwhelming item that is in birth control as well as the natural flow of birth that effects the brain to make me as well as 2-6 % of others homosexual.