Why are you gay? Why am I gay? No, really, like why does it exist? Some say it is because of mental illness, sexual deviancy, or devil worship. While all three of these are certainly the case for me, homosexuality is far too common for that to be the only universal explanation. 

One would think that something that so directly impacts your ability to pass on your genes would be weeded from the population. Yet, studies find on average that 3% to 4% of people are homosexual, which is certainly underreporting. And that’s not even accounting for bisexuals that prefer the same gender, or asexuals, which are about 1% each. That might not seem like a lot, but take it from someone who has spent many long nights studying genetics for fastly approaching final exams, that’s pretty high for something that mostly excludes you from having kids and passing on your genes. Normally those sorts of diseases are one in several thousand, not four in a hundred. 

According to the NY Times, the average American knows 600 people. Therefore, among all your friends, acquaintances, relatives, etc, at least 24 of them have the big gay. Numbers this high must mean that gayness is actually a good thing evolutionarily speaking. 

We do know that gayness is genetic. Certain families have more gay members than others. When one identical twin (who share all the same DNA) is gay the other is probably gay too, but it is less the case if they are fraternal twins (who don’t have the same DNA). Therefore, the big gay must come from your DNA. And we have found several locations on several chromosomes which are associated with gayness. Gayness, like most traits, is probably caused by a number of genes rather than just one. 

If you only have a high school understanding of genetics this may seem odd, but it actually isn’t. Most of our genes are complex traits which do not follow mendelian inheritance of dominant and submissive recessive. That’s why your height and skin color tend to be somewhere between your parents’, not one or the other. Even when you are talking dominance and recessiveness, there isn’t always a 50/50 chance of each gene getting inherited like Punnett squares would have you believe. Some genes tend to get inherited together. An example being that gingers tend to also inherit freckles, green eyes, and the ability to suck out a man’s soul like a dementor. Those genes just happen to be close to each other on the same chromosome.

• Table of Contents:
• Recessive Gay Gene
• Gay Uncle Hypothesis
• Grandmother Hypothesis
• Fraternal Birth Order
• Counter Argument
• Conclusion

The Recessive Gay Gene

A study found that women rate men who they were told were gay as being more attractive than they did when they were told the same men were straight. This of course makes no sense as women definitely wouldn’t have a chance with a guy that only has homolust, but that’s women. You could say that it is similar to how men tend to fetishize lesbians, which of course also makes no sense for the same reason, but that’s men. 

So the hypothesis says that the gay gene is a bit like sickle cell anemia. When homozygous (when you get a copy of the gene from both parents) Sickle Cell Anemia bends your red blood cells into croissants making them worse at carrying oxygen and causing a slow and painful death. However, when it is heterozygous (when you have only one copy of the gene) it gives you resistance to malaria. Since malaria has killed more humans than anything else, including other humans, this is a pretty good trade off. Therefore having heterozygous gayness is beneficial in some way. Good enough to justify when it becomes homozygous, pun intended.

Another study posits that the benefit may be that incomplete gayness makes men more feminine, which makes them more attractive to women. Think of how many teengirls have posters of boy bands on their walls. This is supported by the fact that, statistically, gay men have more effeminate traits than nongay men. Whatever gene or genes causes gayness also cause a number of physiological and behavioral effects, many of which people tend to associate with being emasculine. I’m not saying that all gay guys are feminine. I’ve met several gay guys who are quite a bit more masculine than the average straight. What I am saying is that twinks and gay femboys exist. Like me!

Men are four times more likely to be homosexual than women are. This could be explained by the gay gene being an X-linked recessive gene. Recessive genes on the X chromosome are about four times more likely to affect men. They only have the one X chromosome, therefore any recessive genes on it will act like they are dominant. For example; male pattern baldness. The gene for baldness is on the X chromosome, so for a woman to have it she would need to have gotten that gene from both of her parents while a man only needs to get it from one. The reason why you don’t see any bald women is because baldness is exacerbated by testosterone. So even a woman with fully-blown homozygous baldness will only have thinned hair.

Gay Uncles

The Gay Uncle Hypothesis requires a bit of explanation. In biology organisms tend to fall somewhere on the spectrum between r-selection and K-selection. Among other things, r-selecting animals will generally put very little energy into each individual baby so they can make as many as possible, such as bunnies. This is usually something like just laying some eggs in the woods then walking away. Each baby has a very low chance of survival, but there are just so many it doesn’t even matter. As long as two survive, you’re at least breaking even. K-selecting animals are the opposite. They don’t have very many babies, but put a lot of energy into each one, maximizing their chances of survival. 

For multiple reasons ¹ such as being helpless dingo food for the first several years of life humans benefit from being extremely K-selecting. This is why humans typically form pair bonds (monogamous relationships). Fathers could benefit from being dead beat dads who impregnate many women. Some still do that, and they should feel bad about it. It’s much more advantageous to focuses on raising and protecting just one set of kids. Maybe a bunny can make it through life based on instinct without any real father or mother figure. But human children that grow up just one parent don’t tend to be as successful. In fact, humans benefit from having as many parental figures as possible. 

Grandmother Hypothesis

Ever think it’s weird that human woman go through menopause but can live for decades after? I mean, not many species do that (the only other one I can think of are killer whales). There’s usually no evolutionary benefit to live any length of time after becoming infertile. That is, unless a grandmother would benefit from ensuring her legacy by helping her children raise their children. The Grandmother Hypothesis states that this evolved so grandmas can help raise their grandkids. They divert time and energy that would be spend on making new kids on ensuring the legacy of the existing ones.

The Gay Uncle Hypothesis is very similar to the grandmother hypothesis. It states that if gayness is a recessive trait, gay uncles who don’t have kids of their own on account of being gay will have the time and energy to help their siblings raise their kids. If gayness is a recessive trait then the gay uncle can still have it be passed down indirectly through their siblings who are carriers for the gay.

You may be wondering “but Mad Scientist, my gay uncle doesn’t help ensure my reproductive success beyond giving me gifts at Christmas which he would do anyways if he was a heterosexual!”. That’s because we in the western world live in nuclear families where uncles, regardless of sexual proclivities, tend to fuck off and do their own thing. In most of the world and history people live in households with their extended families. You would see your Gay Uncle every day and he would become like a second father to you and your other cousins. Same with your Grandma. 

The gay uncle hypothesis is also supported by the fact that men are four times more likely to be exclusively homosexual while women are much more likely to be bisexual. Men in general are more “disposable” since half the men in a tribe could die and the next generation would be just as large if each man takes two wives. But if half the women die the next generation will be stunted as women are the bottleneck, in terms of baby production. That’s why men evolved to be the hunters, while women evolved to “not do stupidly dangerous things”. It’d be more beneficial in the long term to just have gay uncles but not lesbian aunts. That said, of course, having a lesbian aunts would still be very beneficial for the same reasons. There are arguments that having both a gay uncle and a lesbian aunts is beneficial.

Fraternal Birth Order

The Fraternal Birth Order is a phenomenon that men are more likely to be gay the more older biological brothers they have. The odds increase by 38–48% with each brother, so the chance of gayness in the firstborn son is 4%, then 6%, then 8.5%, etc. Therefore, I can calculate that there was roughly an 18% chance that Michael Jackson was in the closet. 

This phenomenon is usually explained by the Maternal Immunization Hypothesis which posits that the phenomenon is caused by the mother building an immunity to Y proteins in the baby responsible for masculinizing the brain. Perhaps that is the mechanism. But surely such an oversight would have been selected against if it wasn’t beneficial.

If you’re a guy and have a gay younger brother be sure to tell them “you’re welcome!”. And if you are gay and have an older brother be sure to thank them for your gayness. They would probably also be confused if you just said that. So also be sure to send them this article, I need the exposure.

If the Gay Uncle hypothesis is true, then it’d be more beneficial for mothers to have a gay son after they already have several straight children. It is called the Gay Uncle hypothesis for a reason. Gayness isn’t quite as evolutionarily beneficial if they are an only child. There’s still nothing wrong with it, of course, its generally not healthy to be constantly worrying about genetic legacy or anything like that.

Remember that historically, especially during caveman days when we were evolving, infant mortality was significantly higher. People would have a lot more children because most wouldn’t survive until adulthood. According to Infant and child death in the human environment of evolutionary adaptation; 46.2% of people died as children, and 26.9% died as newborns throughout history. Therefore, families would have needed to produce at least ~50% more children than they do now just to break even. This increases the number of older brothers the average man would have, even if those brothers died as babies.

Fraternal Birth Order is only affected by the number of boys produced by a woman’s womb, not whether her gay sons grew up with older brothers. This would mean that gayness was more common historically than it is in the modern western world. So there may have actually been an even larger evolutionary push for gayness than previously thought.

If you factor together that with the more optimistic estimates of homosexuality, asexuality, and bisexuals who prefer the same gender, you could say that we evolved to have perhaps as many as ~9% of the population be gay uncles or lesbian aunts. Though a more conservative estimate would be ~6%. In either case, this is a relatively significant percentage of the evolutionary human tribe. Most extended families would probably have at least one gay uncle. It could potentially outnumber postmenopausal grandmothers depending on life expectancy.

Counterpoints

While gay uncles do seem all well and good there are a few issues. One of which is that I am actually pansexual, which makes no sense given that context. A pansexual uncle might still have kids of their own. 

Also, wouldn’t it make more sense for it to be an asexual aromantic uncle? Then the uncle isn’t wasting their time or energy on a romantic partner and can just focus on helping raise their nieces/nephews. And doing other aro-ace things like eating cake, I guess. (I honestly have no idea what asexuals do if they’re not thinking about sex all the time.) Yet, asexuality is much less common than homosexuality. According to Ipsos, only 1% of the male and female population identify as asexual, pansexual and other, combined.

So why is there such a massive preference for Gay Uncles over Asexual Uncles? It could just be due to evolution picking “good enough” as it often does. It might also be that Gay Uncles can “recruit” other Gay Uncles by marrying them. After all, two gay uncles is better than one, even if one isn’t related by blood. Because of kin-selection, there shouldn’t be any significant drive for people to invest time and energy into children they are not related to instead of children they are related to. However, a gay uncle might invest some time and energy into his in-laws in exchange for his partner doing the same for his own nieces and nephews, then you get more synergy.

In Conclusion

So long story short I don’t know for sure why you or I are gay. I personally subscribe to the gay uncle hypothesis, but the science is still out on the exact mechanism of gayness. There is also a good chance that there is no “big gay”, but rather many “little gays”. Gayness can be caused by any one of these effects. Everyone always asks “why is gay” and not “how is gay”? Gay is good. Why look a gift horse in the mouth? For science! Everything should be looked in the mouth. 

Anyways, I’m new to blogging and the advice is to increase engagement by asking a question at the end of an article. But this topic is pretty spicy and based already so I’m sure there’s gonna be plenty going on in the comments anyways. Should be lots of fun, can’t wait to read that.

Bibliography & Further Reading:

Bailey, J. & Vasey, Paul & Diamond, Lisa & Breedlove, Stephen & Vilain, Eric & Epprecht, Marc. (2016). Sexual Orientation, Controversy, and Science. Psychological Science in the Public Interest. 17. 45-101. 10.1177/1529100616637616.

Nicholas Boyon. (2021, 9 June). LGBT+ Pride 2021 Global Survey points to a generation gap around gender identity and sexual attraction. Ipsos. https://web.archive.org/web/20210610112136/https://www.ipsos.com/en/lgbt-pride-2021-global-survey-points-generation-gap-around-gender-identity-and-sexual-attraction

Sanders, Alan R. et al. “Genome-wide scan demonstrates significant linkage for male sexual orientation.” Psychological Medicine 45 (2014): 1379 – 1388.

Balthazart J. Fraternal birth order effect on sexual orientation explained. Proc Natl Acad Sci U S A. 2018;115(2):234-236. doi:10.1073/pnas.1719534115

Brendan P. Zietsch, et al. Genetic factors predisposing to homosexuality may increase mating success in heterosexuals, Evolution and Human Behavior, Volume 29, Issue 6, 2008, Pages 424-433, ISSN 1090-5138, https://doi.org/10.1016/j.evolhumbehav.2008.07.002.

Anthony A. Volk, Jeremy A. Atkinson, Infant and child death in the human environment of evolutionary adaptation, Evolution and Human Behavior, Volume 34, Issue 3, 2013, Pages 182-192, ISSN 1090-5138, https://doi.org/10.1016/j.evolhumbehav.2012.11.007.