Friday, October 9, 2015

Gay Epi-Marks and Dubious Science

Nature News:
The biology of sexual orientation has been one of the most vexing — and politically charged — questions in human genetics. For the first time, researchers have found associations between homosexuality and markers attached to DNA that can be influenced by environmental factors.

Twin studies and family trees provide strong evidence that sexual orientation is at least partly genetic. When one identical twin is gay, there is about a 20% chance that the other will be as well. But because this rate is not 100%, it is thought that environmental factors play a role as well. . . .

To search for factors that could mediate a link between environment and genes, geneticist Eric Vilain at the University of California, Los Angeles (UCLA), and his colleagues looked at epigenetic markers — chemical changes to DNA that affect how genes are expressed, but not the information they contain. These 'epi-marks' can be inherited, but can also be altered by environmental factors such as smoking, and are not always shared by identical twins

The researchers collected DNA samples in saliva from 37 pairs of identical twins in which only one twin was gay, and 10 pairs in which both were gay. By scanning the twins’ epigenomes, the researchers found five epi-marks that were more common among the gay men than in their genetically identical straight brothers. An algorithm they developed based on the five epi-marks could correctly predict the sexual orientation of men in the study 67% of the time.
Wow, 67% of the time -- I bet I could do better than than just by peeking in their closets. Anyone want to lay odds on whether this finding will hold up over time, or fade away like all other claims about gay genetics have?

This is not science -- this is the desperate search for any correlation that can survive basic statistical tests, so somebody can get a publication and keep his job.

Grrr. Grumble. Grrr.


G. Verloren said...

Let's assume, just for a moment, that there is some genetic influence. It's not inconcievable after all - genes can biologically influence things like our tastes and tolerances for certain foods, so why should sexuality be any different?

The question becomes, just how significant are any such genetic influences likely to be? Because while genes can and do influence our tastes in food, far more important is our cultural exposure. So why should sexuality be any different?

There are people with Southeast Asian genetics who don't like spicy food, and there are people with Scandinavian genetics who don't like dairy products. And presumably if it turns out there are genes for sexuality, you will find that there are some people with "heterosexual" genes who engage in homosexuality, and others with "homosexual" genes that are strictly heterosexual.

And if we assume that certain genes dictate attraction toward one body part or another, wouldn't that also suggest there are genes for other fetishes and attractions? Are some populations genetically predisposed to be attracted to redheads? What about eye color, or skull structure? What about skin tone? What about musculature? What about height? What about body odor?

I'd actually assume we all have some minor degree of genetic predisposition for all of these things and more. But I would argue the effect is so very, very minor compared to the effects of culture. Absent of all other factors, being genetically predisposed toward redheads doesn't mean you can't or won't also be attracted to blondes and brunettes. And at the same time, if you were raised in a hypothetical culture which considered attraction to redheads to be abhorent, you would quite naturally be strongly inclined away from that option.

Sexuality is like any other taste in any other subject. You can shape and develop it over time via experiences. Just as no one is born with an appreciation of Belgian Impressionist paintings and must over time gain one, so too is no one born with an appreciation of one form of physical intimacy or another, and must through exposure come to know those expressions and form opinions about them.

Compare other forms of intimacy, such as hugging. Some people are very prone to hugging, while others are far less so. Would any sane person try to attribute that delineation in how different people engage in physical intimacy strictly to a genetic factor?

Or is it in fact glaringly obvious that how one is raised, and what cultural values one ascribes to regarding the act of hugging, is the chief factor in determining whether someone greets a stranger with an affectionate embrace or an aloof handshake?

Sexuality is experiential, not genetic.

pootrsox said...

If as you say, sexuality is "experiential," then you are, in effect, saying that "conversion therapy" to "cure" homosexuality is in fact a legitimate treatment.

Oddly, however, actual investigation has shown repeatedly that conversion therapy doesn't convert anyone. Those who truly feel sexual and romantic attraction to same-sex others do not lose that attraction.

The gay people I know (and I've known and continue to know quite a few, from my late brother and his friends to my daughter's friends to my own circle of friends) have almost never been ambivalent; they have always known, though often tried to fight, their same-gender attraction.

Further, since most GLBT folks have grown up in a heterosexual home, surrounded by heterosexual images, role models, media examples, etc ad infinitum, the existence of so many GLBT folks surely cannot be simply "experiential."

The act of hugging, or of greeting someone with kisses on one or both cheeks, is cultural-- is experiential. It's an *action.* It may create discomfort in some people who are not used to seeing/experiencing such action.

The romantic/sexual desire for someone is not an action-- it's emotional, and in the case of lust, at least, it's also physical-- but not an action unless the desire is *acted upon.*

I rarely disagree with you, Mr/Ms Verloren, but I think you are WAY off target this time.

G. Verloren said...

Well of course "conversion therapy" doesn't work. That's like if I tried to violently coerce you to stop liking your favorite food. With enough abuse and trauma I could condition a fear response, so that you recoiled from a certain behavior out of instinctual need to protect yourself from further punishment, but the underlying desires would remain.

"Conversion therapy" is entirely illegimate, not just because it doesn't truly work in the way it is intended, but also because it's essentially torturing and abusing someone into submission. It has never been anything other than a brutish form of behavioral conditioning to enforce conformity.

G. Verloren said...

Moving on, I don't buy the "I always knew" argument. That's like saying you "always knew" you liked anchovies, or that you "always knew" you subscribed to Kantian ethics. There is no such thing as a priori knowledge, and human desires are not absolute, objective things. You cannot magically know anything about yourself intrinsically - and if you think you do, odds are incredibly good you're dead wrong.

Note that children don't have sexual urges - you have to hit puberty before your sexual physiology kicks in. Yet children are constantly exposed to human behavior around them - to the cultural expectations of their parents, family, and society at large. By the time we're infants, we've already absorbed a wealth of knowledge about how our society differentiates men and women, and how they're "supposed" to behave. So if you feel that you've "always" been homosexual, even since before your biology was sexually matured, isn't it far more likely that this feeling is the product of your upbringing and experiences?

Here's the kicker - while quite often we may embrace the cultural indoctriations we all receive as children, we just as easily may reject it, depending on our individual circumstances.

A child born to a rural family may chafe at the notion of living the way their parents did. They may desire to move to the big city and abandon an agrarian lifestyle, despite their upbringing. Why? Because they have some genetic predispositions toward urban lifestyle? Or because they aren't satisfied with their current lifestyle and are therefor driven to seek out alternative cultures and ways of thinking and doing things?

A child raised in a heterosexual culture doesn't seek out homosexuality because their genetics are forcing them to. The sense they have of "always having known" isn't special knowledge of some secret inner nature coded into their very being by their genes, but rather a lifelong disastifaction with the culture they grew up in. Despite being reared to accept heterosexuality, some aspect of their experiences has left them dissatisfied with that worldview, and driven them to seek out other options.

It's like when someone has a religious conversion. Despite growing up in one cultural paradigm, for whatever reasons they don't truly accept it and seek out another which better suits them. Would you argue that people who reject the religion of their birth for another were somehow always genetically destined to embrace the latter religion? Converts will often tell you they "always" felt out of place, or like they didn't belong, but is that a function of their biology, or just a longstanding rejection of a culture which couldn't accomodate their individual needs, concerns, and doubts?

Happy and content people don't suddenly undergo extreme paradigm shifts for no reason. It is the unhappy and the discontented who seek out personal changes of these sorts. And it makes absolutely no sense at all to suggest that genetics is the factor which determines whether someone will accept or reject a certain culture, and consequently whether they will either be happy or unhappy.

If homosexuality is genetically coded for, then so must be things like political ideology, religious affiliation, and whether or not one can develop an appreciation for freeform jazz. It's an absurd notion.