Getting Into Your Genes: Gay Sexuality & 'Natural Selection'Getting Into Your Genes: Gay Sexuality & 'Natural Selection'

Getting Into Your Genes: Gay Sexuality & 'Natural Selection'

 

Research into homosexuality has led to interesting and sometimes surprising discoveries, as well as to previously unconsidered questions about the balance between nature and nurture in a person’s sexual orientation. Darwinian insights into evolutionary biology may, indeed, fit comfortably into our understanding of homosexuality and the search for a “gay gene.”

How does gay sexuality fit into sexuality overall – and into Darwin’s theory of “survival of the fittest”? Everyone has a sexual orientation and the natural inclination to respond to our deeply felt desires, whether we choose to act on them or not, but what is the source of these most primal urges? There’s procreation, to be sure, not to mention pleasure. To a Darwinist there’s natural selection, survival of the species, and the need for healthy offspring. And don’t forget genetic predisposition.

 

But where does this leave gay people in the natural order of things?

 

What Role Do Gay People Fulfill?


According to scientists, the occurrence of homosexuality is generally about the same in all races, cultures, and nationalities throughout the world:  Approximately five percent of all men and two percent of women are exclusively same-sex in their desires and practices.

 

 

According to research begun by the Kinsey Institute, more men and women are attracted, in varying degrees, to both opposite-sex as well as same-sex partners than are exclusively gay.

 

If this is the case, and if Darwin is correct, gay people must have some role in supporting the species – if not from direct reproductive strategies, then from another, possibly social, perspective.  Let’s investigate, starting with the biological foundation of the so-called “gay gene.”

 

Is There a “Gay Gene”?


This is a crucial question that geneticists and behavioral scientists are investigating, with some fascinating results.  The search for the evolutionary source of male homosexuality is of great interest to many, including not only evolutionary biologists and experts in genetics, but also psychologists, anthropologists, and researchers in other fields. Their goal? To come up with a credible theory on why people are gay and how this manifests in family genetic lines.

 

In researching human sexuality and sexual orientation, scientists have located the source of sexual arousal patterns in the limbic system of the brain, which controls our most primal urges: feeding, the fight/flight response, and the urge to mate and procreate.

 

Sexual Orientation is Genetic


From an evolutionary perspective, the limbic system includes the oldest structures of the brain. Having located the source of sexual desire in those structures, and having discovered same-sex attraction hard-wired in that region, scientists can assert with a high degree of certainty that male sexual orientation is present from the earliest stages of development in the limbic region – and that it is therefore almost certainly genetic in origin.

 

It’s Genetic, But Not Exclusively


While the basis of male homosexuality is not wholly genetic, it is essentially biological in nature.  In short, it results from a confluence of genes, inherited equally from mother and father, and hormones that are secreted from mother to child in utero.

 

Approximately two decades ago, scientist Dean Hamer found that an area on the X chromosome called XQ28 may have some influence on sexual orientation.  This discovery has become known as the “gay gene”; however, XQ28 is not one gene but a network of genes called an allele.

 

As this allele became the subject of more investigation, additional information came to light.  The surprising results have led to a much-expanded view of how the biological basis of male homosexuality could indeed fit into successful natural selection.

 

Women’s sexuality – and lesbian sexuality – has, lamentably, been much less studied. However, based on the research that has been done, it can be stated that:

 

  • Women in general are more fluid in their sexual response; that is, they are more likely to find both men and women attractive to some degree, whether or not they choose to act on these impulses.
  • Same-sex attraction and sexual identity in women is more likely to have a cultural or environmental basis in origin, as opposed to male sexuality.
  • Much more research needs to be done to understand and build on these findings.

 

Mother’s DNA Plays an Important Role


Some researchers in genetics have studied the XQ28 allele’s role in the mothers of gay men. They have found that when mothers carry the allele, its tendency is to influence her to have a larger number of children than women without it.

 

Women with this allele have also been found to be more attractive to men as mates, in evolutionary terms, which might fit well with Darwin’s notions concerning natural selection. Such women select for the “best” males, those likely to prosper in the competition for a partner. Additionally, the presence of the hormone progesterone in women (which in men may be linked to homosexuality) has been shown to promote extroversion and higher levels of sociability, traits related to evolutionary survival.

 

 

Suppressing Same-Sex Desire


Beyond biology, nurture does, in fact, play a role in the architecture of sexual desire.  Environment and culture influence how one’s sexuality may be expressed, promoted, or suppressed.  Genes are clearly not the only factor in an individual’s orientation.

 

Two major suppressive forces in Western culture have been represented by religion and psychiatry, specifically Freudian psychiatry.  For example, Anna Freud, daughter of Sigmund, practiced what was evidently the first of many iterations of “conversion therapy.” She worked with patients for years to get them to “adjust” to her and her culture’s view of “normalcy”:  a happy heterosexual family, with progeny.

 

The fact is, however, that such so-called “therapy” ultimately doesn’t work in changing a person’s essential sexual orientation, and has been harmful to many patients.  It took decades of failed therapy and patient misery before homosexuality was finally removed from the compendium of psychiatric disorders (not until 1973, in the U.S.).

 

We now know that differences in brain structure are caused prior to birth, in part by hormones, and that these neurological developments cannot be produced hormonally – or any other way – after one is born.  Therefore, change is not possible to one’s essential sexual orientation either as an adolescent or an adult.

 

The “Older Brother” Theory of Homosexuality


One of the most intriguing findings related to male homosexuality is the “Older Brother” theory.  As noted above, researchers have found that there is generally a five percent chance that any male will be born (exclusively) gay.  But, they have also found that the odds of one’s being born gay go up by a factor of 15 to 30 percent for each boy previously born to the mother, despite the fact that the brothers share some genes.  So, the odds of being homosexual for a boy with one older brother would be somewhere between 5.75 and 6.5 percent, with the odds rising for each additional boy in the family.

 

A Social Role for Gay Men in Some Cultures


A separate area of research encompasses both anthropology and sociology.  In Samoa, for example, a prized social role exists for a so-called “third gender,” comprising men who are sexually attracted to men.  Termed the fa’afafine, these men are nurturers, providers, and caregivers, and they are active in child-rearing for their extended families.

 

It has also been found that the fa’afafine are frequently the sons of mothers who have given birth to more children, especially male children. And this may be another key to scientists’ search for an explanation that squares Darwinian theory with biological research:  The role of the gay offspring in the family structure might be to support and nurture, a purpose that enhances family health and unity.

 

A Road Ahead for Research


As we’ve learned, the science of sexuality is a complex one, comprising numerous fields of study.  Much is known, but much more remains to be uncovered. It may not be that there is a “gay gene” per se, but we can be certain that genes play a crucial role and that gay orientation is not a choice made after birth.  Beyond that, however, the possibilities for researchers seem virtually endless.

 

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Kevin Martin is Senior Writer for MagellanTV. He writes on a wide variety of topics, including outer space, the fine arts, and modern history. He has had a long career as a journalist and communications specialist with both nonprofit and for-profit organizations. He resides in Glendale, California.

 

 

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