The Evolutionary Purpose of Male Homosexuality

A recent show on the science channel alerted me to an interesting new hypothesis about the evolution of homosexuality. Contrary to popular thought, it does not appear to be an accident. (If anyone can find documentation about this new hypothesis... let me know). Particularly interesting is the behavior of primate males in family groups. As is well known, apes (such as chimanzees, bonobos, and gorillas) that live in family groups consist of many females, one dominant male that gets exclusive access to mating with the females, and sometimes one or more submissive males that do not have the right to mate with the females. A new scientific hypothesis suggests that our early ancestors (who may have lived in similar family groups) may have developed homosexuality among these "submissive" males. The sexual behavior of the apes currently being studied suggests that male homosexuality has an important evolutionary advantage in family groups. The submissive males engage in homosexual behavior as a way to satisfy sexual instincts... but the advantage goes further than that. By engaging in homosexuality, the submissive males present themselves as no threat to the dominate male and thus promote group harmony, by discouraging male fighting over mates. Furthermore, these homosexual males provided survival advantages to the family group by helping to protect the females and infants from predators and rival family groups and to find food for the group. In this case, the sacrifice of the genetic survival of one individual gave an enormous advantage to the survival of the group. - Which is something evolution has been known to favor.

Although this particular advantage of homosexuality is obsolete for humans, the homosexual orientation would have survived despite that because our society changes far faster than evolution.

So.. for any homophobes that claim homosexuality is "unnatural" - Au Contraire! It is VERY natural, for some people!

Views: 4037

Tags: Science, biology, evolution, gay rights, homophobia, religion

Comment by Pope Beanie on March 9, 2012 at 2:19pm

I think that the kind of same-sex sexual behavior documented in prisons and in overcrowded rat populations is a separate subject from the subject of how sexual preference comes to be in uncrowded populations. Even if there is a nature-induced correlation between over-crowded conditions and less baby making, homosexuality still occurs to a significant extent in uncrowded conditions.

Comment by Rob Klaers on March 9, 2012 at 9:27pm

@Ward ... I see your point. On the other hand, it hasn't been unknown for otherwise straight men to have 'wives' who in prison. Now, that could be argued that it's for general companionship not otherwise available in prison. Though, like my hypothesis does, it plays off what Arch said earlier in relation to over-population. I don't think that's the sole reason by far.. just one of many possibilities which could play off each other. ... For some reason this makes me think of binary coding. Some trigger that flips a genetic switch on (1) or off (0). With the majority of genetic switches determining the final outcome.. Again, just conjecture on my end,

Comment by Ward Cressin on March 11, 2012 at 12:17am

@Shabaka Tecumseh: "... I can say with certainty that it is aberrant in Nature."

Not if you are trying to tell the truth. If you don't have all the facts which you obviously don't then you should listen to those who know more. For example, you might want to read this thread but not comment except to ask genuine questions.

@Rob Klaers - the str8 men in prison having sex has puzzled me - it would be interesting to find out more about the break-down of who does and doesn't engage in prison sex: are there some men who will never (willingly) enage in prison sex? the physiological characteristics recognized in gay men - do only those who engage in prison sex have those physiological characteristics (even if str8 outside of prison)? Does the crowed-rat syndrome provide sufficient explanation for prison sex? And so on.

While homosexuality and evolution are the main ones, there are many questions that aren't being answered because closed-minded theists are figthing against science. And with homosexuality, I worry that when a genetic component is found, theists will choose to terminate gay/lesbian fetuses (in spite of their supposed anti-abortion stance) causing a decline in human civilization.

I have not done a scientific study but in my informal analysis of influential / creative people I have found a high correlation with the physiological characteristics recognized in gays/lesbians. Very few complex traits (like homosexuality) are linked to only one gene. But one gene can link to several traits. While we might joke about theists being sheeple, I think trying to eliminate any gay/lesbian gene(s) would turn humans into actual sheeple (unimaginative drones).

Comment by Rob Klaers on March 11, 2012 at 4:47am

I don't think it would be a question of aborting fetuses, for the theists it would be just a question of attempting to convert them when they were young. I'm sure after awhile there would be a number of 'How to make sure from birth your child isn't gay" programs/books/videos.. Of course you'd have those who'd refuse to believe it even if there was a genetic factor, so you might have more babies given-up for adoption.  Not that there aren't already too many in the system now.  

Comment by Pope Beanie on March 11, 2012 at 6:22am

I strongly suspect that sexual preference has epigenetic causes. If that's true, then it may be possible one day to influence preference biologically, with drugs or some kind of epigenetic therapy (analogous to gene therapy). I wouldn't feel comfortable with messing with such things, but I'll still bet that it's going to happen someday. (The first, successful epigenetic therapies will probably be for curing or mitigating specific diseases.)

Comment by Shabaka Tecumseh on March 12, 2012 at 2:01pm

Ward and YOU know more?  lmao..

ab·er·rant  (br-nt, -br-)

1. Deviating from the proper or expected course.
2. Deviating from what is normal; untrue to type.
One that is aberrant.


"The number of species on the planet that have been documented by scientists has risen to 1.9 million, according to the world's most comprehensive catalogue of plants and animals."

The number of species that people CLAIM to practice homosexuality, 1500 or so..

Please Refer back to the above meaning of aberrant.


As an atheist you should know how unreasonable groups tend to try to prove their point thru "science."   I don't see this homosexual debate as being any different.  Be gay, who cares, but keep it out of the public square..  I found the comments below interesting..maybe they know what they are talking about..

Comment by kris feenstra on March 12, 2012 at 3:08pm

There are very few sources that I will dismiss (almost) categorically, but NARTH fits the bill.  It is, quite simply, not a reliable source.  It has been accused more than once of distorting research results by the respective researchers themselves.  It has a clear agenda and heavy religious bias.  If you'd really like me to go through that article, I'd be willing to make an exception here.

It's odd that you talk about religion abusing science to support its aims, then site a source that in no uncertain terms does that very thing.  Check your sources better.

"The number of species on the planet that have been documented by scientists has risen to 1.9 million, according to the world's most comprehensive catalogue of plants and animals."

The number of species that people CLAIM to practice homosexuality, 1500 or so..

The number of species in which homosexuality has been observed is not meant to be a comprehensive number.  It is based on the species we have observed to the extent we have observed them, which is to say limited observation.  The fact that there are 1.9 million documented species is not in any way relevant.  Sexual orientation will not apply to hundreds of thousands of those species one way or the other.  If we use this sort of thinking, being a mammal is aberrant as the number of documented species don't even number into the tens of thousands.

That said, aberrant may be a fair word to apply to homosexuality or other gender identity issues where biology is concerned.  It really depends on the cause, but its not a question of statistics across species.  Socially, I'm not sure that it is.  If we say that it deviates from the norm, a norm has to be defined, and when it comes to human sexuality, good fucking luck.

I don't see this homosexual debate as being any different.  Be gay, who cares, but keep it out of the public square.. 

Why?  For what possible reason?  Even if we stated that it was a preference for the sake of argument, why should that preference be stuffed into a closet?  I don't agree with many people's preferences in music, or clothes, choice of words, political views (etc.).  Should they all be forced to keep these things out of the public square just to appease me?  Or is it just the minorities that are expected to do this?

Comment by Shabaka Tecumseh on March 12, 2012 at 3:41pm

lol a "norm" has to be defined?...I suppose so if your cultural edict is to be boundless, to expand itself...

However, I think you can use Nature as a standard, but then again, since you are boundless, Nature means nothing to you.

Are "mammals" aberrant among mammals?  You bore me..


Comment by kris feenstra on March 12, 2012 at 3:46pm

None of that has anything to do with what I said.  Please address my actual comments and not the imaginary comments you find convenient.

And yes, norms have to be defined.

Comment by Shabaka Tecumseh on March 12, 2012 at 3:47pm

you don't have to put it in the closet, just not in the public square. 


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