The biological basis of human sexual orientation: is there a role for epigenetic
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The biological basis of human sexual orientation: is there a role for epigenetics?
Ngun TC, Vilain E.
Advances in Genetics 2014
http://www.ncbi.nlm.nih.gov/pubmed/25172350Sexual orientation is one of the largest sex differences in humans. The vast majority of the population is heterosexual, that is, they are attracted to members of the opposite sex. However, a small but significant proportion of people are bisexual or homosexual and experience attraction to members of the same sex. The origins of the phenomenon have long been the subject of scientific study. In this chapter, we will review the evidence that sexual orientation has biological underpinnings and consider the involvement of epigenetic mechanisms. We will first discuss studies that show that sexual orientation has a genetic component. These studies show that sexual orientation is more concordant in monozygotic twins than in dizygotic ones and that male sexual orientation is linked to several regions of the genome. We will then highlight findings that suggest a link between sexual orientation and epigenetic mechanisms. In particular, we will consider the case of women with congenital adrenal hyperplasia (CAH). These women were exposed to high levels of testosterone in utero and have much higher rates of nonheterosexual orientation compared to non-CAH women. Studies in animal models strongly suggest that the long-term effects of hormonal exposure (such as those experienced by CAH women) are mediated by epigenetic mechanisms. We conclude by describing a hypothetical framework that unifies genetic and epigenetic explanations of sexual orientation and the continued challenges facing sexual orientation research.
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So, you're convinced it is largely due to hormone-levels? ::)
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So, you're convinced it is largely due to hormone-levels? ::)
Since the 1990s most of the mainstream researchers talk about the 'homosexualties' rather than 'homosexuality'. There seem to be many pathways to identifying as gay/lesbian and hormone exposure during pregnancy seems to be one of the possibilities.
It certainly works that way for cows.
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it his another nature v nurture debate…it will always be a confluence of a lot of factors
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There are some factors that are more important than others. I kind of worry about WHY people study the origin of homosexuality.
Some gay people study it in the hope that if they can show it is 'biological' then people will accept that it is 'normal'. Despite the history of discriminating against people for inherited differences like skin colour, hair texture, and gender.
My second year genetics professor at University stated that he hoped they could find a 'gay gene' so that homosexuals could be diagnosed in utero and aborted. I'm glad that the 'gay gene' has been disproven.
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So, you're convinced it is largely due to hormone-levels? ::)
Since the 1990s most of the mainstream researchers talk about the 'homosexualties' rather than 'homosexuality'. There seem to be many pathways to identifying as gay/lesbian and hormone exposure during pregnancy seems to be one of the possibilities.
It certainly works that way for cows.
So, you are taking 1 possibility as the only one & even suggesting that is completely why some bulls are attracted to other bulls? REALLY? ::)
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Are you incapable of recognizing the plural in English. ie Homosexualities or many or pathways or 'one of the possibilities'?
AS to Freemartins (female cows who have male twins NOT bulls)
https://en.wikipedia.org/wiki/Freemartin -
So, you're convinced it is largely due to hormone-levels? ::)
Since the 1990s most of the mainstream researchers talk about the 'homosexualties' rather than 'homosexuality'. There seem to be many pathways to identifying as gay/lesbian and hormone exposure during pregnancy seems to be one of the possibilities.
It certainly works that way for cows.
So, you are taking 1 possibility as the only one & even suggesting that is completely why some bulls are attracted to other bulls? REALLY? ::)
Your post is funny, because you accuse him of saying the exact opposite of what he said.
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There are some factors that are more important than others. I kind of worry about WHY people study the origin of homosexuality.
Some gay people study it in the hope that if they can show it is 'biological' then people will accept that it is 'normal'. Despite the history of discriminating against people for inherited differences like skin colour, hair texture, and gender.
My second year genetics professor at University stated that he hoped they could find a 'gay gene' so that homosexuals could be diagnosed in utero and aborted. I'm glad that the 'gay gene' has been disproven.
Ha, more likely now days we're going to be "cured" via gene therapy.
I dunno what I'd do if I had the option.
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There's been sufficient study to indicate that there's not an off/on switch for sexual orientation.
And none of these studies ever talk about bisexuality vs monosexuality. It's a much more interesting question of why humans (unlike our closest relatives the Bonobos) are not universally bisexual.
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Genetics is way more complicated than science is willing to admit. l
Take for example someone's eye color? You can't just go in and switch a gene and get blue eye's. Doing that would only give you a slightly higher chance of having blue eyes. It takes changing a few genes to get blue eyes in humans. But by changing so many genes, you inadvertently change other things as well. One of which is sexuality.
Price cattle farmers have known for decades now that the chance of getting a hetero bull from a genetically altered specimen is about 50-50.
But also look at everything that is genetically encoded that's not obvious. Like the coding for your sense of smell. Some people have lost the sense to smell pheromones from other humans. But oddly enough, they can smell the pheromones from apes.
Another example is taste, some people are genetically wired to taste Cumin like soap or a strong poison. While others taste it like a sweet flavor.
Another example is your sight. You get your spectrum of colors from your parents, but we all don't see the colors the same shades. Because somewhere down the genetic tree, those who didn't need to see a certain color, lost the ability to see it correctly.But in labs all over the world, they have known for a long time that messing with the code of many animals and insects have a super high chance of producing gay results. Such as designing a labrador retriever with blue eye's. He will have blue eyes and be gay. But you can genetically make one that glows in the dark and its hetero. Go figure.
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I think the truth lies in genetics and environment in the womb.
You can have a certain genetic makeup but hormones in the womb can prevent your genetics from fully working.
