LGB NewsStudy: Genetic patterns offer clues to evolution of homosexuality

submitted by Shales123 from nature.com

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[–]PatsyStoneMaverique 4 insightful - 1 fun4 insightful - 0 fun5 insightful - 1 fun -  (7 children)

I don't think they'll ever find a distinct genetic component to homosexuality, beyond maybe a gene that expresses as same-sex attraction. What you do with that attraction is still under your individual control, and it would likely be influenced by your environment.

I think the fundamental issue is that if a gene is found that denotes homosexuality, prenatal testing will be introduced to identify it. If social factors do turn out to influence sexual attraction later in life, therapy will be introduced to correct it.

[–]Elvira95Viva la figa 4 insightful - 1 fun4 insightful - 0 fun5 insightful - 1 fun -  (6 children)

There is no single gene, there is no single gene for anything. It's usually a mix of several genes. But actually the most probable cause is epigenetic not genetic. The hormones in the womb that lead to the development of the sexual part of our brain toward female or male attraction.

[–]PatsyStoneMaverique 3 insightful - 1 fun3 insightful - 0 fun4 insightful - 1 fun -  (5 children)

What study is that from?

[–][deleted] 4 insightful - 1 fun4 insightful - 0 fun5 insightful - 1 fun -  (4 children)

This comes from animal studies where we perform surgeries on them, or flood them with sex hormone at various stages. In humans, congenital adrenal hyperplasia in females gives us a very good clue.

Ultimately, look at the development of the primary sexual characteristics. Genetics works up until a point. The presence and lack of of the SRY gene on the Y chromosome causes the undifferentiated gonads to turn into testes and ovaries, respectively. These, in turn create several horomones, of note sex hormones, and it is the sex hormones that then cause tissue differentiation into the two sets of sex organs. Formation of the penis, scrotum / vulva, vagina, cervix, uterus, etc are keyed entirely off sex hormone (and others made by the differentiated gonads play a smaller role, such as Anti-Müllerian Hormone) as far as we are aware. This is called hormonal organization, and it's not a controversial subject until you get to... It appears to be one mechanism of homosexuality.

It stands to reason, that if sex hormones cause the primary sexual characteristics, that it would also hormonally influence the brain such that the later adult human would want to use their sex organs with the "correct," opposite set. It appears that there are different critical stages where these two developmental processes (sex organs, the brain) take place, such that you can get a mismatch. Boom! homosexual.

Now, we do understand this in 46XX CAH, but in terms of non-CAH male and female non-heterosexuality wrt hormonal organization, we don't know. There are other periods during the developmental phase to adulthood that sex hormones are turned on. E.g. https://pubmed.ncbi.nlm.nih.gov/25012863/ and also Adrenarche, long before Gonadarchy takes place (puberty.)

Many rocks to look under, not much funding.

[–]reluctant_commenter 2 insightful - 1 fun2 insightful - 0 fun3 insightful - 1 fun -  (1 child)

This comes from animal studies where we perform surgeries on them, or flood them with sex hormone at various stages. In humans, congenital adrenal hyperplasia in females gives us a very good clue.

It's funny, I feel like when most people hear "environmental" they don't think of conditions in the womb, they think of like, bullying at school or something. Yet when I've read papers about genetics, they usually seem to be referring to the former.

This is called hormonal organization, and it's not a controversial subject until you get to... It appears to be one mechanism of homosexuality.

It stands to reason, that if sex hormones cause the primary sexual characteristics, that it would also hormonally influence the brain such that the later adult human would want to use their sex organs with the "correct," opposite set. It appears that there are different critical stages where these two developmental processes (sex organs, the brain) take place, such that you can get a mismatch. Boom! homosexual.

Ah, interesting! And this is all regarding women with CAH, right? Wow.

I'd be curious to see how this process differs for bisexuality vs. homosexuality. But of course, it is hard to pull apart that nuance with the transgender movement's attempts to hide/erase the very concept of same-sex attraction and redefine what sexual orientation means..

Many rocks to look under, not much funding.

Insert rant here about other stupid shit countries blow their money on instead...

[–][deleted] 3 insightful - 1 fun3 insightful - 0 fun4 insightful - 1 fun -  (0 children)

It's funny, I feel like when most people hear "environmental" they don't think of conditions in the womb, they think of like, bullying at school or something.

It depends who you're talking to. If someone says "environmental," ask them to define that. Different disciplines use that word to mean different things. The sciences are just as guilty of ambiguity with their words. It took me a little while to unravel that environment to the neuroendocrinologist is... well... everything since inception.

Ah, interesting! And this is all regarding women with CAH, right? Wow.

Well CAH is one oddity that gives us the locus of insight into the phenomena. Theorizing from the margins, not the majority phenomena. If everyone were heterosexual, we wouldn't be having this conversation. Bi vs homo is under-theorized and under-studied.

[–]Elvira95Viva la figa 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (0 children)

Thanks, man. Totally perfect explanation. As rats studies have shown sex hormones create both sex traits and sexuality. We can only use animals studies and experiment technically we cannot do this with human. We use the animals for testing and then see we can find same similarities with humans. It turns out the part of the brain which is smaller in case of male attraction and lower testosterone exposure and bigger in case of female attraction and higher testosterone exposure has been found in brain scans on lesbians and gays individual in comparison with thei heteros parts. You're right, it is a mismatch, something can randomly happens but we are supposed to use sex organs to reproduce with opposite sex, homosexuality is something going against the plane, something randomly happens because hormones in the womb just can vary in quantity