
Study Finds No Single Genetic Cause of Same-Sex Sexual Behavior - yaa_minu
https://www.scientificamerican.com/article/massive-study-finds-no-single-genetic-cause-of-same-sex-sexual-behavior/
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DrScientist
Just because they can't pin something down to a single or low number of genes
doesn't automatically mean there isn't a strong genetic determinant - it just
means it might be spread among many factors, making any one factor hard to
pinpoint.

From a high level view, the idea that something that is so critical to species
survival, like a sex drive, isn't largely genetic determined seems rather
unlikely.

I suspect the situation is something like height - this primer gives a good
overview of properties of something that might be largely genetic but by many
many factors. Also it covers the issue of rare exceptions, being different
from the general rule.

[https://ghr.nlm.nih.gov/primer/traits/height](https://ghr.nlm.nih.gov/primer/traits/height)

Also note height is a continuous function not a binary state of tall or short
- I suspect the same is here - this would easily explain, why some people
feeling they were born that way, and others feel it's more a choice.

~~~
kitawana
> From a high level view, the idea that something that is so critical to
> species survival, like a sex drive, isn't largely genetic determined seems
> rather unlikely.

Actually I found that surprising to hear. We have so many social processes
that in many cases discourage and reduce sexual behavior.

Marriage works against the survival of the fittest you might get from sowing
wild oats, but it's almost universal.

Homosexuality, indeed, is a discouragement to species survival (if I
understand your meaning correctly). Yet you're claiming it is unlikely that it
doesn't originate in genetics?

I don't know, I mean, I basically agree with your final statement - that we
don't actually have a discrete variable here even if we largely see discrete
behavior (since we tend to prefer long lasting relationships, so if you're
F45-55M then you'll probably focus disproportionately on finding an M
partner).

And what it means to be a guy or a girl is definitely not genetic. Most of our
interaction with sexual beings is "pants on". And those pants, and the nature
of our interactions, is hugely cultural determined.

And I think most people have the experience of being attracted to a person
without engaging in any sex-seeking behavior with them. And many people seem
to have experience of the reverse.

Given the cultural and experiential components of sexual attraction, I really
don't think genetics need to be worth that much. Maybe there's some
contribution, but it doesn't seem to have much scope, nor does it need it.

~~~
jayjader
Marriage trades the advantage of sowing wild oats for the advantage of a pair
of committed adults sticking around to raise the children to adulthood.

Survival of the fittest is useless if none make it to reproductive age (or the
opportunity to reproduce), and humans are incapable of fending for themselves
for at least the first couple of years of their lives. Simply reproducing with
many is not a surefire way, and doesn't seem to be the optimal way, of
guaranteeing that your genetic material endures.

Bret Weinstein has some interesting thoughts on the evolutionary merits of
things like marriage and religion, I'd reccommend having a look at his work.

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jawns
The "born this way" aspect of gay activism is trending down, even apart from
the lack of scientific evidence of a strong genetic component.

It was immensely useful during the gay rights movement, especially in the
years preceding Obergefell, as a way to essentially persuade straight people,
"This is not something I can control, so it's not something I can change, even
if I wanted to." There was a de-emphasis on how sexual relationships typically
develop -- through a serious of free, conscious choices to which sexual
partners consent -- and instead an emphasis on sexual attraction itself, which
often does not feel like a fully a conscious choice.

Now, I'm seeing more and more LGB people, especially those under 30, freely
admit what had been considered an open secret: that many of those who insisted
that they were "born this way" actually consider sexual orientation _not_ to
be immutable, but fluid, to various degrees. Whether one has conscious control
over whom one finds attractive at any given time, of course, is another
question, but for a time, evidence for sexual fluidity, especially within the
queer community, was considered potentially damaging to the "born this way"
efforts and de-emphasized or suppressed.

Post-Obergefell, more queer people seem to feel like they've gained enough
legal and cultural ground that they can freely admit it, though. And some do
in an almost defiant way, saying essentially, "So what if my sexual choices
are free choices? If I choose to be gay, who's to say I shouldn't?"

That's a far cry from the prevailing narrative from just 10 or 15 years ago,
when very few gay people would admit that they might have any conscious
control over being gay.

~~~
tomp
I cannot understand how "born this way" could ever possibly not be true. Sure,
today people _can_ "decide" (or whatever) but why would anyone in their right
mind decide to be gay like 200 years ago, and risk being ostracized from the
community, being sexually unsatisfied and/or severely punished (including
sterilization and/or death)?

(Obviously "fluidity" of sexuality does not preclude "born this way" \- it
could be that it's written in your genes that your sexuality would/will change
throughout your life, similar to many people's libidos and/or hair color.)

Edit: on second thought, it's very possible that it could be random
environmental influences (e.g. amount of... I don't know... drums + beech
pollen ... the fetus is exposed to in the womb) - that could be pretty much
orthogonal with genetics, while still leaving the person with "no choice".
It's just that AFAIK most personality traits have a significant genetic
component, either actually genetic or epigenetic [1].

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739500/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739500/)

~~~
simias
>why would anyone in their right mind decide to be gay like 200 years ago, and
risk being ostracized from the community, being sexually unsatisfied and/or
severely punished (including sterilization and/or death)?

I wish it were that simple, but unfortunately pedophilia still exists even
though it fits all your criteria. Clearly some people adopt sexual behaviours
even if it could lead them to a terrible outcome. Actually, some might do it
_specifically_ for that reason and the thrill of it.

You could make the same comment about religion, drugs, literature, politics
etc... It's not rare for humans to adopt behaviors that put them at risk even
if there are no obvious benefits. People routinely endanger themselves while
doing kinky things. There probably are more kinks out there than there are
genes in the human genome. There's clearly a large number of factors at play
here, only some of them genetic.

~~~
ytwySXpMbS
This is assuming being gay is purely sexual, which, despite being called a
sexual orientation, is misguided. There is more to attraction than sex, such
as who you imagine you could be in a relationship with, who you develop
feelings for, and who you love. In other words, while one may be aroused by
certain sexual activities (kinks), no one develops a crush on someone because
of a specific sexual activity.

Being gay isn't a kink, just as being straight isn't.

Straight people continued relationships despite being outlawed, which is the
entire premise of Romeo and Juliet. Would you call Romeo and Juliet's
relationship a kink?

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JohnJamesRambo
This is not really that surprising considering that the closer we look it
seems like all genes affect complex traits, the omnigenic theory.

[https://www.quantamagazine.org/omnigenic-model-suggests-
that...](https://www.quantamagazine.org/omnigenic-model-suggests-that-all-
genes-affect-every-complex-trait-20180620/)

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BiasRegularizer
I have read a few cases of identical twins having different sexual
orientation. Perhaps they are also good subjects of study, since their genetic
make up are so similar, it would be easy to identify if/which genes correlates
to sexual orientation.

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dade_
Garbage in, garbage out. This study doesn't mean anything as it relies on
information provided to 23 and me. The question asked if a person had a same
sex experience, which doesn't mean a person is gay, bi or straight. Further
there are plenty of people that wouldn't answer truthfully to the question for
a multitude of reasons.

Good for advertising clicks and idiotic comments that have already started to
appear.

~~~
buboard
> The question asked if a person had a same sex experience

Yeah i found that weird too. a Sexual experience is not "orientation"

Another interesting thing is that homosexual people use 23andme more
frequently than the rest. Perhaps looking for clues like this

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zed88
The theory of gay gene couldn't have been supported by the evolutionary
algorithms.

Natural selection means that a trait like male homosexuality, if it had a
genetic component, couldn't have persisted over evolutionary time if the
individuals that carry the genes associated with that trait are not
reproducing.

In my observation of two contrasting cultures that I grew up in, it could be
better explained by sociology than genetics.

~~~
Spoppys
Yes it is totally supported by evolutionary algorithms. Traits that are
harmful in some situations and beneficial in others can be passed on, like
sickle cell anemia which gives a degree of protection against malaria. The
same as traits which are beneficial to some of your offspring and advantageous
to others, like a strong jaw. Which would probably look better on your sons
than your daughter.

It can be evolutionary advantageous for some of your kids to come first, even
if it means others come last, rather than all your kids coming second.

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mamon
The key takeway is easily lost:

"genetics seemed to account for between 8 and 25 percent of the behavior. The
rest was presumably a result of environmental or other biological influences.
"

There is a lot of other research which identify these "other biological
influences" as hormonal imbalance during the pregnacy, which in most severe
cases causes a child to be transgender, in milder ones gay (this kind of
explains "drag queens", gay man who identify as male, but still like to dress
up as women sometimes. Not sure if there's a female counterpart to this
phenomenon).

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buboard
I get the sentiment but the title is misleading. There IS a significant
genetic contribution, but it's polygenic.

~~~
DangerousPie
That's why it says "no single genetic cause" and not "no genetic cause".

~~~
Vinnl
Technically true, and I'm sure the title wasn't intended to have that effect,
but judging by the other comments, it appears some people still seem to be led
to believe it meant "no genetic cause" \- so it's still worth pointing out.

But yes, that's not necessarily malice or incompetence on the part of the
title's author.

~~~
lone-commenter
> _But yes, that 's not necessarily malice or incompetence on the part of the
> title's author._

If it's not malice, then it's linguistic incompetence.

~~~
Vinnl
Well, incompetence in that they didn't manage to achieve clarity for all
readers, but not in the sense that someone else would've been able to think of
a better title that _would_ achieve that, I think.

~~~
lone-commenter
Sure they would: "Study Finds No Unique Genetic Cause of Same-Sex Sexual
Behavior".

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CriticalCathed
A lot of otherwise smart people in here didn't read the article and are
popping off about how gays choose to be gay.

The article says that it is a POLYGENIC situation, as in "not ONE gene, but
many."

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fbn79
To make it simple to understand I think "same-sexual behavior" can be compared
to left or right handedness. There is not a single gene that determines it
(probably more than 40) but it is certainly not a thing people can choose or
that can be easily changed during life. More about handedness
[https://ghr.nlm.nih.gov/primer/traits/handedness](https://ghr.nlm.nih.gov/primer/traits/handedness)

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NextHendrix
As someone who knows nothing about this subject, if the cause doesn't appear
to be genetic then what does that leave? Environmental? Something else?

~~~
m4r35n357
What do you think causes big noses?

~~~
bayesian_horse
I would like to say your comment is right on the nose, but it really isn't a
helpful question at all.

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b_tterc_p
There’s plenty of evidence to suggest some portion of likelihood of being gay
is controlled by parental hormones. E.g. the probability of being gay is
observably higher in men born after an older brother.

So... this was obviously going to be true.

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enriquto
If I understand correctly, this result is exactly equivalent to "no single
genetic cause for heterosexual behavior", which does not seem as dramatic.

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draugadrotten
What about genetic causes in the parent(s)? Such as a genetic cause in the
mother affecting the hormonal levels in uterus.

~~~
bayesian_horse
That should still result in specific mutations having significant effects.

And maternal effects are a thing that can be computed statistically, both as a
genetic and environmental factor.

And it's not helpful to confuse sexual orientation with hormonal causes or
effects.

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gingabriska
I wonder what if it's a learned behaviour.

I used to very odd kid and mostly spent my life around girls from very early
age.

I almost never had male friends which ofc changed in late teenage.

Now, don't find females that attractive and mostly spend time with guys.

Don't call me sexist or smth but I find it's more fun to work with guys.
That's my preference.

~~~
tomp
Proximity can go both ways... You might as well develop a strong _liking_ of
girls/women because of proximity.

I've been bombarded from young age (by pop culture, TV, magazines, porn) by
thin women wearing make-up. I have a strong sexual preference for thin (fitspo
thin, not anorexic thin) women and a strong dislike of women wearing make-up.
Go figure...

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draw_down
I always thought the claim of a genetic cause for sexuality was a bit
premature. Even if one is “born this way”, that doesn’t necessarily mean it’s
genetic.

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verroq
I find it difficult to believe a universal genetic cause since same-sex
relationships generally don’t produce off-spring and would be naturally
selected out.

~~~
bayesian_horse
In fact I read some time ago that one mutation that does have a small
contribution to sexual orientation, has the same allele frequency in most
Human populations, suggesting that even the "gay" allele is positively
selected for.

A Human individual's fitness affects the chances of his whole family. And it's
just not true that Homosexuals don't have children. In practice they have
fewer children, but more than you might think.

