Is sexual orientation genetic or environmental? What two new studies reveal



There’s nothing new to be gay, but that hasn’t stopped scientists from trying to figure it out.

Over the past two decades, many researchers have focused on the notion of the “gay gene” – biological proof that one is “born that way”.

It makes sense: our genes can influence who we are, and psychologists argue that sexual orientation is not a conscious choice. It goes without saying that there could be some genetic basis to which we become sexually attracted.

But more recent research has both confirmed and debunked the notion of a genetic basis for sexual orientation. Instead of a single gene (or a marker on a gene) that determines sexual orientation, there are many genes with markers linked to same-sex attraction.

For example, in 2019, researchers studying these markers and homosexual attraction said Reverse: “This finding suggests that at the genetic level, there is no single dimension ranging from opposite-sex preference to same-sex preference.”

But that’s only part of the story.

Two new studies published on Monday, one in Nature Human Behavior and the other in Scientific reports, shed more light on the complexities of sexual orientation and how heavy the scientific study of the subject is. They also highlight three key factors:

  1. Our own sexual orientation can be a lot smoother than we thought.
  2. The same group of genes that may being associated with homosexual sexual behavior may confer some evolutionary advantage.
  3. There are inherent dangers in focusing on genetics over sexual orientation.

Genes and sexual behavior – The first author, Brendan Zietsch, associate professor of psychology at the University of Queensland in Australia, and his colleagues attempted to find out why genes associated with homosexual sexual behavior continue to flourish. Their study was published in Nature Human Behavior.

In a press release, the study’s authors report:

“Because [same-sex sexual behavior] SSB confers no obvious direct benefits for reproduction or survival and may divert mating effort from reproductive opportunities, its widespread occurrence in the animal kingdom and human cultures raises questions for evolutionary biology.

Using information from UK Biobank and responses to the sexual behavior questionnaire from hundreds of thousands of individuals, the study team analyzed the genomes of 477,522 people in the UK and US who had only had homosexual interactions.

They compared this dataset to the genome of 358,426 people in the same countries who had only had opposite-sex encounters.

The team found that genes linked to homosexual behavior are also found in heterosexuals. This genetic profile across groups is associated with having more sexual partners.

A man waves an LGBTQ flag in front of the Bosnian parliament.Getty

The authors postulate that the number of opposite-sex sexual partners could be evolutionarily advantageous, as it could lead to more children.

In turn, they argue that their findings help explain why homosexual sexual behavior has persisted throughout the evolution of the human species: these genetic effects may have been evolutionarily favored as they are associated with more d ‘children.

Ultimately and critically, the authors argue, genes can less have to do with sexual preference and Following to do with sexual openness / will.

The ethical debate – Other scientists warn against extrapolating information about sexual preferences or behavior from genes.

In a commentary article published alongside the study, ethicists Julian Savulescu, Brian D. Earp and Udo Schuklenk distill the debate on whether or not this type of research will lead to societal abuses.

They write:

“One can imagine technologically advanced repressive regimes where homosexuality is banned, requiring genetic testing on embryos and fetuses, destroying those willing to SSB, or testing children early in life for their propensities. Others will respond that the world (or at least parts of it) has become more tolerant of homosexuality, so maybe these concerns are overblown.

What matters, they argue, is creating a society in which this type of genetic research cannot be abused to further harm anyone, let alone already marginalized groups.

They write: “Genes shape, limit and provide opportunities for who we are and who we can be, both as individuals and as members of communities. To prepare for new research on polygenic behavioral traits, including SSB, we need to reshape society. “

Ilan Dar-Nimrod, researcher and professor at the School of Psychology at the University of Sydney, recounts Reverse “genes take an oversized agency ”in the minds of researchers in sexual behavior.

“The genetic code of properties,” he explains. “And although they can predict a lot of things, a lot of people have this individual view: if you have the gene, you are going to be that and you cannot change it.”

It’s just not in line with what we know about the science of genetics, he says.

On Monday, Dar-Nimrod and his colleagues also published a study on sexual preferences, this one in Scientific reports. The results of this study support his claim that preferences are more malleable than genes suggest.

Sexuality is a specter

In their study, Dar-Dimrod and his colleagues asked 420 cisgender people between the ages of 18 and 83 to read literature. Study participants identified themselves as exclusively heterosexual.

“We just changed the way they look at it.”

One group read literature on sexual preferences as a fluid spectrum. For example, one of the articles discussed gradations of sexual attraction to men and women and noted that people can fall anywhere along the continuum. Another article explained that sexual orientation can change over time, shifting throughout life instead of being fixed. The control group read unrelated articles.

After reading the literature on sexual fluidity:

  • Twenty-eight percent of the participants in the experimental group were more likely to identify as not exclusively heterosexual.
  • Nineteen percent said they would be more likely to be willing to engage in same-sex sexual activity.

The rate of participants identifying themselves as “non-exclusive heterosexual” more than quadrupled after the experience.

In contrast, in the control group, only 8% of participants identified as “not exclusively heterosexual” after reading literature unrelated to sexual preferences.

Dar-Nimrod says there were several results that surprised him:

  • How many people in the experimental group identified themselves as “not exclusively heterosexual” as a result of the experience?
  • People actually expressed their willingness to engage in homosexual activities after the experience.
  • That even when weighed against the literature refuting the idea of ​​sexual preference as a spectrum – one of the papers argued that sexual orientation is indeed fixed – participants consistently gave more credit to literature that discussed a sexual spectrum

Dar-Nimord does not believe that the literature he had the treatment group read really changed who the participants were attracted to.

“We haven’t changed the underlying direction,” he says. “We just changed the way they look at it.”

While our genes can predispose us to certain traits and conditions, when it comes to behavior, our society, environment, and relationships all play an important role in our behavior.

“Do we really need to suggest that [queer people] are born with a certain gene to accept them and their relationships with other consenting adults? Said Dar-Nimord. “I do not think so.”

Once we realize that we are not in fixed black and white boxes, we have the freedom to explore the gray area most of us belong to. At least, that’s what science can really show.

Nature Human Behavior abstract: Same-sex sexual behavior (SSB) in humans is inherited, confers no obvious direct reproductive or survival benefits, and may divert mating effort from reproductive opportunities. This presents a Darwinian paradox: why was the SSB maintained despite an apparent selection against it? We show that the genetic effects associated with SSB may, in individuals who engage in only opposite-sex sexual behavior (OSB individuals), confer a mating advantage. Using the results of a recent genome-wide association study of SSB and a new genome-wide association study on the number of opposite-sex sexual partners in 358,426 individuals, we show that, in OSB individuals, the genetic effects associated with SSB are associated with greater sexual partners of the opposite sex. Computer simulations suggest that such a mating advantage for alleles associated with SSB could help explain how it has been maintained during evolution. Caveats include the cultural specificity of our UK and US samples, the societal regulation of sexual behavior in these populations, the difficulty of measuring mating success, and the fact that the variants measured capture a minority of the total genetic variation. features.

Scientific reports abstract: We examined whether the self-reported sexual orientation of heterosexual individuals could be influenced experimentally by manipulating their knowledge of the nature of sexual orientation. In Study 1 (180 college students, 66% female) participants read summaries describing evidence of sexual orientation existing on a continuum versus discrete categories or controlling manipulation, and in the study 2 (460 participants in a nationally representative Qualtrics panel, 50% female) further read summaries describing sexual orientation as fluid versus stable throughout life. After reading the summaries, participants answered various questions about their sexual orientation. In Study 1, moderates and political progressives (but not conservatives) who read the Continuous Manipulation subsequently reported being less exclusively heterosexual, and regardless of their political alignment, participants reported less certainty about their sexual orientation, in relation to the witnesses. In Study 2, after exposure to fluids or continuous manipulation, heterosexual participants were up to five times more likely than controls to consider themselves not exclusively heterosexual. Additionally, those with the continuous condition reported less certainty about their sexual orientation and were more willing to engage in future same-sex sexual experiences than those with the control condition. These results suggest that non-traditional theories of sexual orientation may lead heterosexuals to adopt less exclusive heterosexual orientations.


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