New Study Reveals Link Between Sexuality and Serotonin in Mice


New research on female lab mice suggests that there is a link between sexual orientation and serotonin levels in the brain, according to a report from The Atlantic on a paper by researchers from Peking University:

We won't likely trace human sexual orientation to a single gene, but research has made it apparent that sexuality can be influenced by manipulating genes, hormones, and neurotransmitters. Altering balances of testosterone and estrogen has been shown to affect sexuality, and imbalances of the neurotransmitter serotonin can make us hypersexual. In mice, serotonin has been tied to sexual preference — mice bred without certain neurons have shown "no sexual preference." But scientists have never "reversed" any species' sexual orientation by messing with their genes.

That is, until now. "Researchers led by Shasha Zhang…bred certain female mice that lacked either serotonin or certain neurons that release serotonin in parts of their brains" before observing and identifying their changes in sexual behavior and preference. The results were telling:

Those mice with the mutations showed preferences for sniffing the head and genital areas of other female mice, as well as "try[ing] to grasp … females by the waist before mounting on their back. … Females displayed strong mounting preference toward the females, mounted female targets with shorter latency, higher frequency, and longer duration."

"Mutant females lacking serotonergic neurons" showed preferences for females over males. Zhang and company concluded that not having certain neurons that release serotonin "cause[d] a reversal of sexual preference, revealing a role for [serotonin] in regulating sexual preference."

For now, the ethical and scientific implications of similar findings in human beings is a different matter.  However, the linkage remains an interesting reference point to tide over the scientifically-minded.  

Note: The Atlantic assures readers that the term "mutant" is "just a trade term used in every article about genetics ever, describing changes relative to a given starting point."     


  1. Chris says

    @AlanBrickman So all other research is supposed to stop until cancer is cured? The cure for cancer is also hundreds of little cures, not one cure.

  2. says

    Is this research applicable to females only ?
    Does it mean that in males the lack of serotonin influences our orientation towards males ?
    Eh, what does it mean ?
    I guess I should withhold my judgment until I understand what’s going on .

    Well, at least that harpie, Bachmann, is crawling back to the swamp……that cheers me up.

  3. helen says

    A cure for homosexuality would be a miracle and a blessing. I applaud all of this research. I am sure Christians everywhere would be willing to donate funding to such an admirable cause. We need to understand the causes of homosexuality. So many young people are ensnared in this unhealthy lifestyle. There will eventually be a cure and many people will choose to take it. Then we will find out if the gay lobby really believes in free choice and individual liberty. Or if they will want to ban it. I just pray that I live to see the miraculous day.

  4. Urmensch says

    Hopefully we’ll find a cure for religious delusion first making the idea of curing homosexuality unnecessary.

  5. Billy Crytical says

    Until the “heterosexual or else” threat is lifted from gay people, gay people will not be safe. Heterosexuals hate gay people. Regardless of what’s happened recently with laws, heterosexuals want heterosexual children. Gay people do not have independence.

  6. helen says

    @Urmensh: The truth will set you free. Please read the New Testament. Christ said a man should leave his father and mother and cleave to his wife…Not his hisband. Why wouldn’t you want a cure. Then those who wish for god-centered family lives but are afflicted with same gendered attraction will have that option.

  7. helen says

    @Urmensh: The truth will set you free. Please read the New Testament. Christ said a man should leave his father and mother and cleave to his wife…Not his hisband. Why wouldn’t you want a cure. Then those who wish for god-centered family lives but are afflicted with same gendered attraction will have that option.

  8. Paul R says

    Because so many people are naturally born without serotonin neurons. I don’t understand this study either.

  9. The Prophet says

    @helen: I was speaking to God the other day and he told me to tell you that you are wrong. He also told me to tell everyone that some guy named Leviticus messed up the whole Bible a long time ago because he was mad at his boyfriend and added some crap He never said.

    Don’t believe me? Prove I didn’t speak to Him.

  10. helen says

    I did not even go back to the Old Testament…I spoke of what Jesus, himself said. Read Mark 10….if I am not mistaken.

  11. says

    A cure for irrational bigotry would be the bigger miracle and blessing, helen. Your personal religious beliefs are irrelevant to everyone but you. Now gather your skirts and run back under the troll bridge before Jesus slaps you.

  12. Billy Crytical says

    helen is a typical HATERosexual. Haterosexuals seek out gay people to attack.

  13. Rich F. says

    @ helen: Don’t you have some goats to stop from crossing a bridge or something? Why would anyone care what your particular book of fiction has to say about anything? I don’t go around telling you to live your life according to the tenets of the “Lord of the Rings” trilogy, or Heinlein’s unabridged “Stranger in a Strange Land,” do I?

    On second thought… go read the unabridged version of “Stranger in a Strange Land,” and live your life by its tenets. You’d be much less of a judgmental twunt, that’s for damned sure.

  14. Rich F. says

    @ helen: oh, and you’re going to spout Jesus’s alleged words from the gospel, why don’t you tell the class what Matthew 19:12 says?

  15. Brent says

    Why are these creepy Chinese scientists obsessed with finding a cause for homosexuality? How about they find out the cause of heterosexuality?

  16. Anastasia Beaverhausen says

    I can’t wait for DARPA to weaponize this into a fabulous gay bomb.

  17. Alphonso X+1 says

    Alphanso X (Alphanso the Wise) of Spain, observed to an astrologer computing tables of planitary positions, that had he been present when GOD was setting up the heavens, he would ask “Could YOU not use a simpler system”?

    I think that we have not yet finished reading the first page on the “Book of Sexuality”.
    When I was on Prozac (a SSRI), I had no libedo. So apparently Serotonin has a role in sexuality, perhaps a major role.

  18. Paul R says

    Why do people respond to trolls who apparently get enormous joy from posting on blogs?

  19. Caliban says

    I don’t know, maybe this is a piece of the puzzle but here’s an interesting little factoid. SSRI anti-depressants increase the amount of serotonin in the blood yet I’ve never seen even a single article that claims they turn gay people straight.

    However, I *have* seen articles that say if you give SSRIs to “extreme” religious folk, the type of people who NEVER shut up about Jesus for instance, their religious monomania either lessens or goes away. Not that they stop believing, mind you, but they stop obsessing about it.

    Maybe we ought to start putting them in the water along with fluoride?

  20. Ben Nevis says

    I hate this sort of thing. It sort of implies that homosexuality is wrong and it needs curing. Screw dat Wally. I’m happy just as I am and the world would be a more screwed up place without gay ppl.

  21. ratbastard says

    My understanding is an decrease in serotonin levels corresponds with a decrease in aggressiveness, sexual arousal, etc. Which is why people on SSRIs often appear to have a ‘flat’ affect and are impotent. At least that’s my understanding. On the other hand, amphetamines increase serotonin levels often resulting in hyper sexual arousal and aggressiveness. Cocaine of course also increases serotonin levels.

  22. Ain't it Funny says

    Even though Helen sounds a bit “cray cray” it is an interesting question as to why homosexuality can’t be studied like any other facet of human behavior is studied and *IF* (big if) they are able to identify a chemicals in the brain that determine it that they can’t offer the person the “choice” to either change or not? In a truly free society people should be able to do whatever they wish as long as they are not hurting others…isn’t that our platform?

  23. Just_a_guy says

    @”ain’t it funny”: um, sure, that’s an element of our platform, but it’s alone incomplete. Also, gay is GOOD. Y’all, gay is good. It’s also natural. Gay is also God-intended (or at least any conception of God that I can conceive). Further, if I accepted your point, aif, I could only do so if you acknowledged that in said hypothetical world, we ought to fully embrace those who would choose to contribute in their lives AS gay people. See, aif, you may make subhuman noises, aif aif, and maybe you should seek help with that. But don’t force that on others.

    Helen of Troll: Your type of thinking “justified” way too many human atrocities in the past 500+ years. From genital mutilation as standard practice to attempted genocide of Jews, enslavement of people with dark skin to “justified” segregation by race–all wove religious bigotry into their supposedly modern/mechanized/”scientific” worldview. Hot, you are deep into gender cleansing–something no less atrocious or evil than ethnic cleansing. Hot, you need to go take a cold shower and try to wash away your bigotry, please. Go, now.

  24. Really says

    The problem is that without negative external pressure no one is going to want to change their sexuality. I say the choice is offered, but only once bigots like Helen are removed from society.

    Personally id love to see a cure for religious delusion, clearly that’s an imbalance and unhealthy. To aggressively believe the unbelievable is a mental illness, not an innate property. Yes, Helen, you are mentally ill.

  25. says

    Now I’m even more confused than ever.

    My homosexuality is not caused ; it just is.

    Shouldn’t they be asking a more valid question, what causes heterosexuality, …..there are more of them after all. Shouldn’t the researchers start there……after all being attracted to females is so unfathomable …at least to me ( Gold Standard).

  26. Rexford says

    Well, then, if it’s biological, then I guess God wants me to be this way, since He doesn’t make any mistakes. Isn’t that how it should go?

  27. Ain't it Funny says

    “Just a Guy” of course we should embrace people who “would” choose to be gay, but that doesn’t mean we can’t explore the science until we do.

    Not sure what you point is.

  28. anon says

    These mouse vector studies are often so flawed they can safely be ignored. The basic problem is that the mice don’t represent human biology in any meaningful way. However, they’re cheap and as a scientist you can’t get your career in trouble if you’re doing what everyone else is doing, even if the science is worthless. Read the various articles in Slate about using mice for more info.

  29. Caliban says

    @Ain’t It Funny, while pretty much anything and everything about humanity is or has been studied (even when it was stupid and/or redundant), research on or about gay people or homosexuality in general has CONSISTENTLY been used as a weapon against gay people, to deny rights. It isn’t just idle curiosity, just as Phrenology or medical “studies” of Jews under the Third Reich weren’t scientific inquiry without an agenda.

    Take the “gay is a CHOICE!” argument for instance. Many scientific studies have backed up the claim that being gay is NOT a choice, that some combination of genetics and conditions in the womb predetermine sexuality. Did that end the argument and shut up the Religious Right? Of course not! The newly “enlightened” homophobes (those who admit they’ve read and accept the research) have just moved their argument, changing it to “being gay might not be a choice but you can choose not to act on it!” They’re like Lucy holding the football in a Peanuts cartoon. No matter what we do they’re going to keep moving the ball!

    So any research that implies sexuality can be changed “if you want,” will just be used as a weapon against those who DON’T want to do it. Their argument would just be “Why should we give rights to people who could change if they wanted to?”

    I think it can and should be argued that gay people are just a fact of life and, more than that, enrich humanity by offering a slightly different POV and talents that are not in spite of our sexuality but in part a result of it. There’s a stereotype that gays are “artistic” and “creative” and certainly we have had tremendous impact not just in the creative arts but in other fields like education and medicine. Which isn’t to say that all gay men should be pushed into those fields or have those skills, but that we actually serve an important function that society itself would be poorer without us.

  30. says

    Some explication for this experiment is that somehow the depletion of serotonin affected somehow the olfactory system, and the mice didnt knew who is the male and who was the female.

    The mice relay on the olfactory system to determine the sex of the other mice.

  31. sandi says

    It’s interesting that removing the serotonin didn’t affect other behavior but it’s the first time they’ve actually been able to reverse sexual interest from one gender to another in both male and female mice. I’ve read scientists who’ve always felt it was a about sexual orientation in humans, not hormones, in spite of what Simon LeVay and others have thought (not that fiddling with hormones hasn’t been shown to have an effect…after all, congental adrenal hyperplasia in women does result in a much higher percentage of lesbians than in the rest of the female population, but it’s still not the answer to most of lesbianism.) These people I know believe that something kills off some brain cells (probably from an early infant infection) that makes a neurotransmitter necessary for recognition of suitable mates, the way narcolepsy is the result of the killing off of only about 30-50K brain cells that make a neurotransmitter (hypocretin) that, they’ve just discovered, is responsible for keeping people awake by making them responsive to light. 30-50k cells is like tiny, miniscule, itty bitty out of all of our brain cells, yet people who have all or even some of them knocked out being to conk off without warning, and many of them go into a state where their muscles become rigid and they can’t move, all because of this tiny number of cells that they think the flu or some other such common bug has knocked off.

    It wouldn’t surprise me at all if we find out, as they think, the same thing is what occurs in the brain of the pre-gay kid. It could happen in the womb or very early childhood and nobody would know, just as in narco.

  32. sandi says

    Correction: I meant to type that I’ve read from some scientists that they’ve felt it was always likely to be about a neurotransmitter, not about hormones.

    I’ll add: serotonin in humans likely affects other neurotransmitters so will see where this leads, but I think it will indeed tell them something about human sexual orientation, both hetero and homo.