Richard Dawkins And The Evolution Of Homosexuality (VIDEO)

My last post, The Gay Brain, really got some of you talking. The central thesis of the video was that even though scientists have yet to identify the "gay gene," the vast consensus in the scientific community is that homosexuality has a strong genetic basis, based on multiple studies that point to heritability of LGBT identification and behavior. Many scientists believe that there is not just one gay gene, but in fact a multitude of genetic markers that are either switched on or off by a complex dance of epigenetic and environmental factors. Either way, it cannot be denied that being gay is rooted in one's biology.

At the end of the post, I asked what all of this means from an evolutionary perspective. Chosenfew79 left a comment that summarizes the questions that were raised by many of you:

If we look at this question from the perspective of modern humans, it appears to be somewhat short-sighted, since we all know that gay men and lesbian women can produce offspring just like heterosexual men and women can. They have all of the requisite anatomy, capability, and even the drive to have children, they just don't engage in the behavior necessary to procreate. In addition, from a modern perspective, we know that homosexuality is not a behavior per se, it is an identity, a point that was raised, sensitively and beautifully, by many commenters throughout this discussion.

But from the perspective of simple scientific curiosity, I think that chosenfew79 raises an extremely valid query. Natural selection posits that genes which increase reproductive success (those with higher fitness) will be selected for by the changing environment, and those with lower fitness will be selected against, ultimately washing them out completely, or at least keeping their numbers significantly low in a population. Neutral mutations (those that neither increase nor decrease an organism's reproductive success) will remain in relatively constant numbers throughout the population. From a modern perspective, I am very cautious to apply Darwinian natural selection to the human population, since we have decommissioned evolution in so many ways (medicine, technology, etc.). I personally believe that we have become a species of artificial selection pressures. But, from a historical perspective, it is an interesting exercise to look at how genetic contributions of homosexuality may have been preserved and passed down by our ancestors.

Nobody knows evolution better than Dr. Richard Dawkins, and his take on the evolution of the "gay gene" is fascinating, elegant, and quite clever. Bear in mind, the language used in this interview may not be safe for work.

What do you think?

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Comments

[Karissa36]

12:27 PM on 12/15/2011

There is another factor to consider. An example is sickle cell disease and malaria. Malaria used to be both common and deadly in certain places. Sickle cell, (SC), is a genetic disease. If you inherit the SC gene from only one parent, you will be a carrier of the disease, but not adversely affected. If you inherit the SC gene from both parents, you will have full-blown sickle cell. Prior to modern medicine, you would have died young, almost always before reaching reproductive age. (If both parents are SC carriers, there is a 1 in 4 chance their child will inherit SC from both, and have the full-blown disease. There is a 2 in 4 chance their children will be carriers.)

As late as the 1960's, in some areas of the world, people with the SC gene out-numbered the ones without it. What was the evolutionary advantage of the SC gene, when it caused early death before reproduction, in a significant number? It was that carriers of the SC gene had a much greater resistance to deadly malaria, and thus survived in greater numbers. On average, 1 out of every 4 of their children would die from SC, but 2 would survive malaria.

It is not necessary for gay individuals to increase the evolutionary advantage for survival. Clearly, individuals with full-blown sickle cell did not do so. It is possible that being a carrier for gay genes, but not homosexual, creates a survival advantage.

[Cathy Creswell]

11:23 PM on 11/13/2011

Our closest cousins, the bonobos are very sexual as has been shown elsewhere. They have sex in all combinations during their entire lives. Perhaps we are not so different. We have a capacity to experience sex for it's own sake. Sexual experimentation is common in nature, and in humanity. It has been limited by culture and religion, but it's still there as a desire. Chimps and orangutans also engage in occasional same sex experimentation. Especially among the young males who are not dominant yet, and females who are closely bonded. It just our nature.

[Pullingthewool]

03:44 PM on 11/09/2011

This is entire article can be summed up by the opening disclaimer, in the first paragraph, 3rd sentence: " ***Many scientists believe*** that there is..."

A ***belief*** is not science folks.

But how many environmental factors effect our human bodies? Such as what is hidden in our food, things like soy, pesticides, heavy metals, and then also examining the DNA (blood) to identify common things heavy metals, GM foods (they are finding that GM corn pesticides are in the stomachs and blood streams of mothers and infants born to them, though the FDA told us they wouldn't). These are just examples.

But comment from "Weiqiu Liu" makes a good point re: the Swedish twins study, found that individual environmen­t (such as illness and prenatal experience­) WAS the largest factor in homosexual­ity by far! And brain developmen­t is strongly affected by fetal developmen­t environmen­t, so the brain scans of adults in your previous article do nothing to disprove that

I'm not a fan of Dawkins, he is a closed-minded, scientist. If a discovery jumped right up in his face, he'd miss it completely.

[Angel1999]

10:33 AM on 11/10/2011

The reason scientists believe this is because the scientific evidence supports it, not because an idea popped into their heads and sounded good.

[Maezeppa]

12:09 PM on 11/12/2011

When scientists believe something, it is because there is a credible basis for the belief. It's not like religious faith. There is some interesting recent study done in Italy that shows a specific type of male homosexual has female relatives who are more fecund than the heterosexual control group. The "belief", or hypothesis, is that a gene when expressed in women is a super-male-attractant and when expressed in males does much the same thing. Clearly an evolutionary advantage. Homosexuality has been around as long as humans and contains an interesting set of challenges. I'd also love to know what forms the basis of your belief that Richard Dawkins is close-minded. Maybe you want to see him that way.

[evolutionisit]

08:50 AM on 11/09/2011

Read: Richard Dawkins' The Selfish Gene
Also read: Dr. Robert Trivers' The Folly of Fools
Scientific evidence trumps....well most things, at the very least...

[been2there]

01:33 AM on 11/09/2011

From the strictest view of passing on one's DNA, it can be argued that homosexual individuals are more likely to help raise their relatives children, thereby increasing the probability of the genes they share will survive.

[Maezeppa]

12:12 PM on 11/12/2011

It can be argued but doesn't make a whole lot of sense. There are other theories that seem more solid. "Homosexuality in males may be caused in part by genes that can increase fertility in females, according to a new study. " http://bit.ly/hIVnZG

[Shila Avissa]

11:38 PM on 11/08/2011

I'm still very interested in hearing Dr Richard Dawkin's take on the gay female gene though...

[Angel1999]

10:34 AM on 11/10/2011

Yes, the things that lead to homosexuality in males versus females appears to be quite different.

[Karissa36]

12:52 PM on 12/15/2011

Considering the status of male/female relationships and power structure over the history of the world, I seriously doubt that the vast majority of lesbians had the choice not to reproduce. ( I am not trying to be inflammatory towards men, so please don't take offense.) The fact is that most women were controlled by men, and needed men to survive. Heterosexual sex, and thus reproduction, was mandatory for the majority of women in these circumstances.

Assuming that the gay gene (like most other genes) is not sex-specific, the fact that lesbian women were forced to reproduce, all by itself could account for the continuation of the gay gene.

[Just4theHalibut]

03:59 PM on 11/08/2011

The original conversation and most commentators here seem to be focused on male homosexuality. Is it possible that (if one assumes that genetic basis of homosexuality is same in male and female) its continued prevalence in human population is at least partly the result of forced marriage and/or rape committed on lesbian females? Not a happy thought, but seems like it shouldn't be ignored.

[ihsxps]

11:02 AM on 11/10/2011

I hate to say it, but it actually does seem to go without saying.

[jimboy71]

03:38 PM on 11/08/2011

"They have all of the requisite anatomy, capability, and even the drive to have children, they just don't engage in the behavior necessary to procreate".

But this is entirely untrue. Even today, many gay men and women have children, and for as many reasons as there are colours in flowers.

The issue is trying to shoehorn human behaviour and child-rearing into the nuclear family mould using bronze age mythology. This has been the heritage of a transition from hunter-gatherer to agricultural to urban modes of living.

This doesn't negate the fact that we are still hunter gatherers, pyschologically, and biologically, and that our "natural" kin systems don't conform to the ones we impose.

Until the advent of transcendentalist religions based in radical patriarchy, there has always been a place for gay people in a given culture. It is only the mythology of the ominpresent daddy that excludes gay people as a corrolary to the exclusion of women.

[Syllogizer]

01:23 AM on 11/09/2011

You are the one doing the shoehorning. Only recently have gay men and women been able to have children, using tecnologies that imply questionable ethics, such as "artificial insemination".

Throughout most of human history and pre-history, in particular during the time that had at least some impact on evolution, the only way "gay men and women" could have children was by suspending their own inclination long enough to complete a heterosexual act.

And of course, there is absolutely NO evidence to support your purely political comment " there has always been a place for gay people in a given culture."

[jimboy71]

10:27 AM on 11/09/2011

Ah,

No. My bits all work and I can assure you, if I wanted a child, there would be a line up of women happy to oblige.

Moreover, I would actually do the deed, as I have done in the past. She might even really enjoy it...after all, my girlfriends had no complaints.

I think it has something to do with being interested in HER pleasure. I wonder what your partners have to say about you?

The rest of your argument is rot.

European theatre. European Opera. Chinese Opera. Two-spirited peoples of North American Natives. African shamanic traditions. Mesoamerican shamanic traditions. All of Greek and Roman culture...from politics to the arts to the everyday peasant.

And the list goes on and on. Homophobia as institution is relatively new, culturally speaking. And you are a fine example of what it produces. El sueno de la razon produce monstruos.

[KYZipster]

07:50 AM on 11/10/2011

The evidence is there alright, difficult to come by in this culture that was much like Iran a short time ago, insisting that homosexuality simply doesn't exist. If a person is curious enough, they can find it and there is nothing political about historical fact.

[Riyter]

02:25 PM on 11/08/2011

I always thought that it made sense to have homosexuals in a population because until recently that might have been a group that did not have children, which would make them more available to help those that did have kids. It makes sense to me that a population is better served with a few pregnant women but not all women pregnant. Someone needs to help with protection, carrying heavy loads,etc. that pregnant women might have a hard time doing. It irks me when people ask what good to a society is having older females who can't breed any more -- duh!

[Paintio]

12:27 PM on 11/08/2011

That 'gay uncle' thing bugs the hell out of me. It seems to assume that one needs to be hetero to hunt, or male, or something. That seems to me to be a very hetero-centric/male view.

[Syllogizer]

03:22 PM on 11/08/2011

This is but one of the many reasons why this "gay uncle" guess does not even deserve the name, 'hypothesis'.

[Angel1999]

07:53 PM on 11/08/2011

Why not? It's a testable conjecture based on findings in other species in which non-breeding males provide a benefit to the group.

[Daniel Hicks]

12:57 PM on 11/10/2011

What sort of sophisticated wordviews do you think they had in prehistoric times?

[Weiqiu Liu]

11:59 AM on 11/08/2011

"Many scientists believe that there is not just one gay gene, but in fact a multitude of genetic markers that are either switched on or off by a complex dance of epigenetic and environmental factors."

But do any prominent geneticists believe there is only a single gay gene? Saying "Many scientists believe that there is NOT JUST ONE" right after saying "the vast consensus in the scientific community is that homosexuality has a strong genetic basis... implies that it is taken for granted that there is at least one gene, and thatmany genes support your assertion further (i.e., the 'more genes, the better' as far as evidence goes). In reality, the opposite would be true. Thinking of many vague genes, rather than knowing a specific single gay gene simply points to the (correct) conclusion that attempts to find the single gay gene have failed, and now they have given that up and are expanding the search wider.

"...dance of epigenetic and environmental factors. Either way, it cannot be denied that being gay is rooted in one's biology."
But environmental factors directly contradict your genetic conclusion. And the largest well-run study of the causes of homosexuality, the Swedish twins study, found that individual environment (such as illness and prenatal experience) WAS the largest factor in homosexuality by far! And brain development is strongly affected by fetal development environment, so the brain scans of adults in your previous article do nothing to disprove that

[jimboy71]

03:42 PM on 11/08/2011

The issue here is that there is no way to prove whether the environmental influence is merely a trigger for a genetic sequence. We simply haven't enough genetic information to make that call.

Because of this, studies can merely suggest that environmental factors are at play. They cannot confirm them. Moreover, the experiments required to confirm these results are likely entirely unethical.

The question, biologically speaking is uninteresting to me.

[Weiqiu Liu]

06:26 PM on 11/08/2011

Yes you can, since identical twins share virtually all their genes (minus random mutations and epigenetic changes), and other twins share half the genes but the exact same environment. So you can compare the genetic similarity between identical twins and fraternal twins to the degree that they share their sexuality. Though what they did was much more complicated, that is the general reasoning behind the methods used in the Swedish twin study.

"Because of this, studies can merely suggest that environmen­tal factors are at play. They cannot confirm them. Moreover, the experiment­s required to confirm these results are likely entirely unethical."
You can say that with almost everything on the effects of genes and enviroment on human behavior. , This study looked at every single twin in all of Sweden, so it was very high powered and completely avoided a selection bias.

"The question, biological­ly speaking is uninterest­ing to me"
Then why did you read an article on it, and read and respond to comments on said article?

[Marc NL]

11:39 AM on 11/08/2011

Evolution is about the survival of the fittest. Offspring is no longer needed to survive. in order to survive you now need other skills. Humans simply adapted (evolved) to a new environment. Sexuality is no longer a factor.

This is just my simple opinion about this.

[jimboy71]

03:44 PM on 11/08/2011

"Evolution is about the survival of the fittest".

Incorrect. That is but one element of selection. Also, fitness itself is fluid, and dependent on the envrionment of adaptation. It is very simplistic to flourish this one sentence as if it explained all of evolution.

Moreover, we haven't adapted to the new environment yet. Not enough time has passed.

[Marc NL]

03:56 PM on 11/08/2011

I understand. I didn't had much time when I wrote it. What I said probably was simplifying it a bit much.

[welthar]

09:56 AM on 11/08/2011

really liked Hawkin's theory of the gay gene being developed or supressed based on environmental stimulus. this would make a lot of sense.

[youtoothree]

12:47 AM on 11/08/2011

"From a modern perspective, I am very cautious to apply Darwinian natural selection to the human population, since we have decommissioned evolution in so many ways (medicine, technology, etc.). I personally believe that we have become a species of artificial selection pressures."

can you please explain to me what you mean by decommissioned evolution in medicine and technology? I think you have a misconception of the word "evolution". It has neither gone away or become irrelevant in either category. as for artificial selection, that says nothing about demise of evolution. It operates the same way whether it be artificial or natural.

[Angel1999]

09:29 AM on 11/08/2011

I think she means that we have taken ourselves out of the natural processes upon which evolution would work. People who might normally die young and before they could pass on the genes that would have killed them at a young age, are now being treated and can live to reproductive age, for example.

[Paintio]

12:24 PM on 11/08/2011

That is just the overriding condition in which evolution continues to work. Natural selection has just gotten considerably more complex in the ongoing 'age of specialization.'
It's also to hard get an overview of something that one does everyday.

[ihsxps]

11:40 AM on 11/10/2011

The principal evolutionary trajectory for homo sapiens sapiens seems to be "neoteny," where adults retain juvenile characteristic into adulthood: exaggerated head size, loss of bodily hair, delayed onset of puberty, etc. Medical science--through forceps delivery, c-section and other interventions--actually seems to be accelerating this process, rather than supressing it.

http://en.wikipedia.org/wiki/Neoteny

[Karissa36]

01:44 PM on 12/15/2011

Girls are reaching puberty at much younger ages than previously.

[Mendezio]

08:05 PM on 11/07/2011

Lets assume children are created completely free of mental content and are only free to learn through experience and perception. In this scenario anything that this hypothetical child mentally becomes must have originated from a perceivable source, or more clearly said, the Earth.

Why wouldn't the origin of homosexuality be environmental and sociocultural alone?

[jimboy71]

04:02 PM on 11/08/2011

This is called hard Empiricism, and while it still has some acolytes, there is very good scientific evidence to refute it as a tenable position.

See the case of John/Joan, a boy who was mutilated in a botched circumcision and whom a pyschologist tried to make into a girl, following exactly the principle that the mind is a "tabula rasa".