Two new studies and other analyses of the inheritance of sexual orientation in humans has indicated that same-sex sexual behavior has multiple genetic components but not a specific gene.
There might be thousands of genes influencing same-sex sexual behavior, each playing a small role, scientists believe. The new study found that all genetic effects likely account for about 32 percent of whether someone will have same-sex sex. Using a big-data technique called genome-wide association, the researchers estimated that common genetic variants — single-letter differences in DNA sequences — account for between 8 percent and 25 percent of same-sex sexual behavior. The rest of the 32 percent might involve genetic effects they could not measure, they said.”
The study analyzed 408,000 men and women from the U.K. Biobank between the ages of 40 and 69, and 70,000 customers of 23andMe with an average age of 51: “The researchers mainly focused on answers to one question: whether someone ever had sex with a same-sex partner, even once.”
Andrea Ganna, lead author and European Molecular Biology Laboratory group leader at the Institute of Molecular Medicine in Finland, said the research reinforces the understanding that same-sex sexual behavior is simply “a natural part of our diversity as a species.” The new study, published Thursday in the journal Science, is not the first to explore the link between genetics and same-sex behavior, but it is the largest of its kind, and experts say it provides one of the clearest pictures of genes and sexuality.
… Let’s put the Genes of “Breeders” under a Microscope too, eh?!?
Some observations:
1) Not sure why they are referring to genetics in relation to same-sex sexual BEHAVIOR rather than same-sex sexual ATTRACTION. That certainly limits their sample and BEHAVIOR is not necessarily indicative of innate orientation. I knew I was attracted to men long before I ever acted on it.
2) I would think 32% genetic contribution to same-sex behavior is too low. (Again I question why “behavior” rather than attraction or orientation). AnecdotalIy, based on conversations I’ve had, would guess that many gay men would put genetics closer to 90% responsible for one’s same-sex attraction.
3) I think the flaw here is that there was no “control group” of heterosexuals studied to find a “straight” gene. Hetero-attraction has to be determined genetically, so why not same-sex attraction. Looking for some aberrant or abnormal gay gene takes us back to the Homosexuality as Disease model.
Reminds me of the old “Heterosexual Questionnaire” that turned those questions straights asked back to them: “So what do you think CAUSED your heterosexual orientation?”
4) When I lived in Southern New England I knew literally dozens of (French-Acadian) men who came from what I call the Gay Triangle in northern Maine (Madawaska-Van Buren-Presque Isle). I knew of one family with 7 siblings: 6 males were gay or bi; one lesbian.
Something for the next scientific study.