A Possible Hereditary Model Explaining Homosexuality in Men

Timothy Kincaid

June 18th, 2008

“I say it’s a choice ‘cuz if homoseeeexshality was heriditary then why din’t they all die out? They ain’t got no kids.”

Some people believe that if homosexuality had some genetic contributor then the reduction in average number of children born to gay males would over time cause this gene to become extinct. However a new model challenges this assumption.

From Fox News

In 2004 the researchers studied about 200 Italian families and found that the mothers, maternal aunts and maternal grandmothers of gay men are more fecund, or fruitful, than average.

Recently, they tried to explain their findings with a number of genetic models, and found one that fit the bill.

“This is the first time that a model fits all our empirical data,” said Andrea Camperio-Ciani, an evolutionary psychologist at the University of Padova in Italy who led the study. “These genes work in a sexually antagonistic way — that means that when they’re represented in a female, they increase fecundity, and when they’re represented in a male, they decrease fecundity. It’s a trait that benefits one sex at the cost of the other.”

If the same genes create both homosexuality in men and increased fertility in women, then any losses in offspring that come about from the males would be made up for by the females of the family.

The research results can be found on PLoS ONE

We show that only the two-locus genetic model with at least one locus on the X chromosome, and in which gene expression is sexually antagonistic (increasing female fitness but decreasing male fitness), accounts for all known empirical data. Our results help clarify the basic evolutionary dynamics of male homosexuality, establishing this as a clearly ascertained sexually antagonistic human trait.

Drowssap

June 18th, 2008

I read the whole thing and it was interesting.

Of all the gay gene theories this is the only one that isn’t completely silly. Even so I doubt it will pan out.

Anyway it’s one thing to prove that a gene could theoretically survive through algebra. It’s another to find this gene and prove it exists. We need more meat on this one.

Side Note:
If male homosexuality is the trade off for extra female fertility it DEPENDS on this extra fertility for it’s survival. Family size is now based on choice, not fecundity. With most women having 2 children that gene wouldn’t last many more generations.

Liz Ditz

June 19th, 2008

Gene transmission doesn’t depend only on a parent-child relationship, as primates live in social groups. A productive question would be: does having a second degree relative who is homosexual, and therefore non-reproductive, increase an individual’s reproductive success? And if so, how?

Consider this scenario for early human societies: having a non-reproductive uncle or aunt, who continues to live with, and contribute economically to, his or her sibling’s family, means that there are more resources (food and child care) for the sibling’s children, thus giving the sibling’s children a reproductive advantage.

Drowssap

June 19th, 2008

Liz Ditz

I understand the principal of kinship but I don’t buy it for a lot of reasons. I should note that Simon Le Vay doesn’t buy this one either.

Consider this.

In every society there at least as many young, infertile women as there are gay men. Large numbers of these women devote their energy towards caring for the small children of their relatives. So it’s a gene? Mathematically speaking you could prove that this trait could be spread through genetics. But it’s not. Nearly all infertility in young women is the result of illness, and most of this is caused by STDs. Scientists would laugh at anyone who suggested otherwise. This version of the gay gene theory is just as silly.

Richard W. Fitch

June 19th, 2008

Even if this model and its data provide a clue for understanding male homosexuality, where do lesbian women fit into the equation?

Brady

June 19th, 2008

I’ve always found the, “if it’s genetic, they’ll all die out” explanation against genetic origins of homosexuality particularly elementary. A basic understanding of recessive genes answers this pretty easily.

Ephilei

June 19th, 2008

This theory is merely a biological version of anthropological models that have been a while. All these models say “evolution favors more than individuals who have lots of offspring, it also favors groups that produce many offspring and the healthier the better.” Lesbians and gays can certainly offer advantages to other children in their social group which tends to also be a similar gene pool.

Besides the fact that plenty of gays and lesbians do have children. The norm used to be, and still is in most of the world, that sex is mandatory for producing children or satisfying your husband and you don’t have to enjoy it or have a physical attraction to your partner. Alan Chambers and all the ex-gays who still appear gay are able to have kids.

Robguy

June 19th, 2008

You have to remember that the people saying if it were a gene they’d all die off – are the same people (usually) that believe in a talking snake. Science isn’t their best subject.

Drowssap

June 19th, 2008

You guys have to keep one thing in mind. You are right, due to reasons we can’t yet understand SSA might be largely or entirely due to a gene(s).

But so far the evidence doesn’t support that. The latest Swedish twin study suggests that genes play a minor role.

“Overall, the environment shared by twins (including familial and societal attitudes) explained 0-17% of the choice of sexual partner, genetic factors 18-39% and the unique environment 61-66%. The individual’s unique environment includes, for example, circumstances during pregnancy and childbirth, physical and psychological trauma (e.g., accidents, violence, and disease), peer groups, and sexual experiences.”

To the best of my knowledge every twin study since 1991 suggests the same thing. Even Bailey’s 1991 twin study put concordence at just 50% and that was the high water mark. His 2000 study which he felt was much better dropped the concordence rate to 20%.

That doesn’t mean there aren’t dozens of genes that increase or decrease the odds someone will be gay. Those are certainly out there and scientists will eventually find them.

There could even be a rare mutation that makes someone gay all by itself. But rare is the key word.

Emily K

June 19th, 2008

“Environmental factors” doesn’t mean necessarily that psychological trauma is what causes gayness 80% of the time. I never say “Never”, as in psychological trauma “never” causes gays to happen – but I find it to be as rare as genes playing a factor 100%. More likely that factors beyond anyones control, such as hormonal exposure in the womb, play a large part. There are actually fewer genes that play a part in left-handedness than sexual orientation.

Drowssap

June 19th, 2008

Emily K

I never say “Never”, as in psychological trauma “never” causes gays to happen

I highly doubt that significant numbers of men turn gay because of traumatic events. For instance a dad dies in a car wreck or a child goes through a messy divorce. But I wouldn’t count out some sort of general physical trauma at a very early age or in the womb. I don’t mean a konk to the head but possibly something as lame as a flu virus exposure or something like that.

Example:
Exposure to meningitis before the age of about 3 can switch kids from right to left handed. The earlier it happens and the worse the infection the more likely the brain will switch hand orientation from right to left. It sounds totally crazy but it happens.

Chapter 2 in this paper talks about that phenomenon.

CPT_Doom

June 20th, 2008

Even if this model and its data provide a clue for understanding male homosexuality, where do lesbian women fit into the equation?

Well, of course we don’t study lesbians because they’re women and don’t count [end snark]

Seriously, I know I saw research some years ago that argued bisexual female primates were more favored by primate males because their children were more likely to survive into adulthood (because the female lovers would share food with one another’s children during times of stress/famine). Certainly we have seen the same attraction among straight men, and anecdotally it appears that women are far more likely to be bisexual than men. Thus, it is possible that lesbianism, while fulfilling many of the same supportive roles for human society, may be generated by a different mechanism, perhaps a gene for bisexuality that is expressed very strongly and elimates the attraction to men a bisexual woman would typically feel.

In general, though, I think the entire topic of the biological basis of human sexuality should be settled by a cursory examination of fetal development. We know that 1) all humans are 50% male and 50% female; 2) all embryos are basically the same; 3) a delicate dance of genes and hormones must occur in utero for a human baby to form. We also know that the physical process of fetal development can create intersexed people – who are physically, and often genetically, more of a mixture of the two genders than a typical human. Why then would it be shocking that some humans do not follow the strict male/female stereotypes?

lurker

June 20th, 2008

I read a study a while back that said that 2nd, 3rd, and 4th sons are much more likely to be gay. The authors of the study concluded that in-utero chemistry changed with multiple male births, effecting subsequent fetuses (although they didn’t have a mechanism).

Just seems that this recent finding could be confounded with that earlier finding – women with more male births could have this “younger-gay-sons” effect AND are more fecund (‘cuz they’ve HAD 2nd, 3rd, & 4th sons who are more likely to be gay).

Rich

January 10th, 2009

>> A basic understanding of recessive >>genes answers this pretty easily.
Huh? Recessive genes for blonde hair, etc., are not manifest in every generation, but are transmitted in the usual way. A gene that keeps you from reproducing can’t even make it to the next generation let alone skip to the one after that.

Arnold

January 22nd, 2009

The fact that this study was conducted by an “evolutionary psychologist” show that the conclusions are biased. “Evolutionary Psychologists” also refute any cognitive basis for moral turpitude beyond social influences. Further, there is no presence of a control group in this study, which negates it’s validity. This study has not been replicated by other scientists, and therefore, is questionable at best.

Leave A Comment

All comments reflect the opinions of commenters only. They are not necessarily those of anyone associated with Box Turtle Bulletin. Comments are subject to our Comments Policy.

(Required)
(Required, never shared)

PLEASE NOTE: All comments are subject to our Comments Policy.

 

Latest Posts

The Things You Learn from the Internet

"The Intel On This Wasn't 100 Percent"

From Fake News To Real Bullets: This Is The New Normal

NC Gov McCrory Throws In The Towel

Colorado Store Manager Verbally Attacks "Faggot That Voted For Hillary" In Front of 4-Year-Old Son

Associated Press Updates "Alt-Right" Usage Guide

A Challenge for Blue Bubble Democrats

Baptist Churches in Dallas, Austin Expelled Over LGBT-Affirming Stance

Featured Reports

What Are Little Boys Made Of?

In this original BTB Investigation, we unveil the tragic story of Kirk Murphy, a four-year-old boy who was treated for “cross-gender disturbance” in 1970 by a young grad student by the name of George Rekers. This story is a stark reminder that there are severe and damaging consequences when therapists try to ensure that boys will be boys.

Slouching Towards Kampala: Uganda’s Deadly Embrace of Hate

When we first reported on three American anti-gay activists traveling to Kampala for a three-day conference, we had no idea that it would be the first report of a long string of events leading to a proposal to institute the death penalty for LGBT people. But that is exactly what happened. In this report, we review our collection of more than 500 posts to tell the story of one nation’s embrace of hatred toward gay people. This report will be updated continuously as events continue to unfold. Check here for the latest updates.

Paul Cameron’s World

In 2005, the Southern Poverty Law Center wrote that “[Paul] Cameron’s ‘science’ echoes Nazi Germany.” What the SPLC didn”t know was Cameron doesn’t just “echo” Nazi Germany. He quoted extensively from one of the Final Solution’s architects. This puts his fascination with quarantines, mandatory tattoos, and extermination being a “plausible idea” in a whole new and deeply disturbing light.

From the Inside: Focus on the Family’s “Love Won Out”

On February 10, I attended an all-day “Love Won Out” ex-gay conference in Phoenix, put on by Focus on the Family and Exodus International. In this series of reports, I talk about what I learned there: the people who go to these conferences, the things that they hear, and what this all means for them, their families and for the rest of us.

Prologue: Why I Went To “Love Won Out”
Part 1: What’s Love Got To Do With It?
Part 2: Parents Struggle With “No Exceptions”
Part 3: A Whole New Dialect
Part 4: It Depends On How The Meaning of the Word "Change" Changes
Part 5: A Candid Explanation For "Change"

The Heterosexual Agenda: Exposing The Myths

At last, the truth can now be told.

Using the same research methods employed by most anti-gay political pressure groups, we examine the statistics and the case studies that dispel many of the myths about heterosexuality. Download your copy today!

And don‘t miss our companion report, How To Write An Anti-Gay Tract In Fifteen Easy Steps.

Testing The Premise: Are Gays A Threat To Our Children?

Anti-gay activists often charge that gay men and women pose a threat to children. In this report, we explore the supposed connection between homosexuality and child sexual abuse, the conclusions reached by the most knowledgeable professionals in the field, and how anti-gay activists continue to ignore their findings. This has tremendous consequences, not just for gay men and women, but more importantly for the safety of all our children.

Straight From The Source: What the “Dutch Study” Really Says About Gay Couples

Anti-gay activists often cite the “Dutch Study” to claim that gay unions last only about 1½ years and that the these men have an average of eight additional partners per year outside of their steady relationship. In this report, we will take you step by step into the study to see whether the claims are true.

The FRC’s Briefs Are Showing

Tony Perkins’ Family Research Council submitted an Amicus Brief to the Maryland Court of Appeals as that court prepared to consider the issue of gay marriage. We examine just one small section of that brief to reveal the junk science and fraudulent claims of the Family “Research” Council.

Daniel Fetty Doesn’t Count

Daniel FettyThe FBI’s annual Hate Crime Statistics aren’t as complete as they ought to be, and their report for 2004 was no exception. In fact, their most recent report has quite a few glaring holes. Holes big enough for Daniel Fetty to fall through.