Birth control pill may alter women's taste in guys

New research suggests that the birth control pill can affect some women's taste in men. The reason is that the pill seems to shift a woman's preference toward men who share a particular group of genes with them. The genes, the major histocompatibility complex (MHC) gene family, are expressed in odor. From Scientific American:
Women who start or stop taking the pill, then, may be in for some relationship problems. A study published last year in Psychological Science found that women paired with MHC-similar men are less sexually satisfied and more likely to cheat on their partners than women paired with MHC-dissimilar men. So a woman on the pill, for example, might be more likely to start dating a MHC-similar man, but he could ultimately leave her less sexually satisfied. Then if she goes off the pill during the relationship, the accompanying hormonal changes will draw her even more strongly toward more MHC-dissimilar men. These immune genes may have a “powerful effect in terms of how well relationships are cemented,” says University of Liverpool psychologist Craig Roberts, co-author of the August paper.
"Birth Control Pills Affect Women's Taste in Men" (Thanks, Marina Gorbis!)

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  1. I hate to burst your bubble, David, but this is not new research.

    I’ve been reading about this in magazines like Discover and Muscle and Fitness since 1999.

  2. I missed the definition in the intro paragraph. Sorry, I have a bad habit of skipping to what’s quoted. i have an additional bad habit of firing off stupid questions based on little information. The two bad habits don’t get along well at all.

  3. So birth control pills will alter the normal course of human evolution, eh?
    OTOH, what human activity doesn’t?

  4. It’s always neat when you find science that explains events that have occurred in your life.

    Before breaking things off with my college sweetheart I switched birth control three times, trying out new types. I eventually decided to stop using hormonal birth control. Specifically I stopped about a month and a half before we broke things off.

    I think articles like this are important reading for women looking to settle down. It could help inform their decisions.

    I’m glad that I’ve never been on the pill with my husband, and now that I’ve read this I never will.

  5. #7: nice story.

    It reminds me of my neighbours back in LA.

    Their respective therapists switched their respective medications on the same day, and they broke up within hours of coming home!

    If memory serves about the last time this subject about birth control pills came up, I think it had something to do with changing your immune system, and therefore the pheremones you would be attracted to.

  6. I’ve gone on and off the pill while with the same person. It affects me in lots of ways – but not who I’m attracted too. But really interesting research. It makes me wonder what effect pg hormones could have on who a woman is attracted to.

  7. The problem with things like this is that, yet again, women are reduced to some set of hormonal impulses that guide our existence. We’re not able to make choices about our lives or our bodies, and are just at the mercy of our body chemistry and how things that gave us the reproductive freedom enjoyed by men “negatively” affect us.

    The research is not new, and it may or may not be true. But I think the conclusions, at least framed in this fashion, are demeaning and dehumanizing.

  8. I am pleased by the ever-increasing pile of evidence that “love” is a chemical reaction. It supports my deep, black cynicism and my rejection of romance as irrational monkey behavior.

    {sniff}

    i’m so lonely

  9. What I find more interesting about the article (or at least your synopsis of it) is that it says that women on birth control are more likely to pick men who are less likely to satisfy them sexually.

  10. #8:

    Their respective therapists switched their respective medications on the same day, and they broke up within hours of coming home!

    I doubt any changes in meds would kick in that fast. I doubt their prescriptions were filled that fast. If they were both seeing therapists (separate therapists, at that), I suspect meds had little do with their break.

  11. I guess the specific way it happens is interesting, but who, with even a basic understanding of what birth control pills are, could possibly be surprised that they have *some* effect on one’s sex drive?

    (Not picking on the pill, btw, and I’m definitely not an “all-natural” type. Living IS better through chemistry.)

  12. I’ve found time and again that my taste in women can be altered significantly by intake of substances in the PBR family.

  13. You say that like it’s a bad thing.

    Oh, it’s not. But if you’re going to be a crazy monkey, be a crazy monkey. Don’t wrap it all up in DeBeers ads and Meg Ryan.

  14. @Nora (9)
    This New Scientist article talks about men’s response to where women are in their menstrual cycle. Apparrantly men can’t conciously tell any difference between the smells, but their testosterone levels are affected.

    Annoyingly it’s a subscription-only article and, for some reason, it won’t let me in right now. If I can speculate though, testosterone is involved in agression and horniness so it seems plausible that a man’s attraction to women could be changed by the woman’s hormonal birth control.

    If I’ve guessed your gender wrong and you’re asking about a woman who may or may not be on bith control being attracted to another woman who may or may not be on birth control… Not a clue. I’d guess “yes” based on other research I’ve seen on women responding to each others’ pheromones, but can’t present a shred of evidence or guess which way(s) the effect would be.

  15. First of all… the article says that the pill causes women to prefer people with dissimilar genes to their own, not similar ones. You’ve got it backwards.

    Secondly – birth control pills also increse the chances of breast cancer. This isn’t new, but it’s apparently not widely known.

  16. #20: It’s a good thing this didn’t come to light in the 60s. It was controversial enough then, but I can hear the radio now: “The birth control pill has been scientifically proven to increase rates of promiscuity, miscegenation, and communist leanings in children.”

  17. Known about this research since the early 90’s. Don’t get on BC until you’ve met your mate – or unless you are not ready to procreate or marry. It’s actually pretty critical and I expect contributes to unexplained infertility. In unpublished data inbred groups like Mennonites and Amish have a healthier population then should be by chance and an indication is becuase of MHC assortative mating – and indeed their MHC complexes in married couples are dissortative not similar.

    Some will poo-poo it, but trust me, a man that smells good when you are off the pill is someone you will stay with.

    -Ethel

  18. @Daemon: I think it’s one of the things that doctors are supposed to tell women when they start their prescription. This might just be the UK though.

    Cancer Research UK’s cancer stats page on Breast Cancer Risk Factors has the numbers for England in 1996.

    Using oral contraceptives give you a relative risk of 1.24 plus or minus 0.09… which means it increases the chances by a scary-sounding 24%.

    A woman’s chance of developing breast cancer by the age of 40 is 1/200 = 0.5%. An increase of 24% on that brings you up to (0.5*1.24=) 0.62%. So it’s an increase, but not a huge one. Women who only take the pill until age 30 have an even smaller change – from 0.0011% to 0.0014%. Big percentage changes over a small base.

    Women should definately understand this, but I don’t think it’s something worth worrying about too much when compared to the risks of getting into a car accident or whatever else they get up to.

  19. Bugs, if someone had told me that the pill could increase my risk of breast cancer even just the tiniest bit, I would never have taken it! I had no idea. My doctor never ever once brought this up before prescribing them for me at the age of 16 (when I didn’t even need them). Every time I see the doctor they practically force a script on me, which I never fill. Doctors don’t care what the woman wants, they just want us on the pill!

  20. Purly, I’ve got to disagree with you. I’ve never experienced a doctor trying to “force” me to be on the pill, or withholding any salient information. In fact, I have a medical condition for which the pill is probably the best treatment. Even if that wasn’t true, the ability to control whether and when I get pregnant is a very great good.

    I think the real-life impact of the effect described in this article is likely to be small. Relationships are a hell of a lot more complicated than similarity or dissimilarity of a single gene group — even just from a biochemistry perspective there’s a lot more going on. I’m always wary of these kinds of psych studies.

    As a matter of fact, the article — if not the original paper, which I have not yet dug up and read — is based on a fundamental misunderstanding of how the pill works. It does not mimic pregnancy. It mimics the state of already having ovulated. Those are two different hormonal states.

    As for the breast cancer link — my understanding is that the research is inconclusive. Moreover, birth control pills reduce the incidence of certain other cancers (see this National Cancer Institute FAQ). It’s certainly a choice you have to make for yourself — different people make different risk assessments, and experience different side effects — but the pill brings health benefits too.

  21. Relationships are a hell of a lot more complicated than similarity or dissimilarity of a single gene group — even just from a biochemistry perspective there’s a lot more going on.

    Right on, Caroline. I agree with all your other words, too.

  22. If you can, I would highly recommend getting the original paper. The citation is as follows:

    Roberts, S. Craig, Gosling, L. Morris, Carter, Vaughan and Petrie, Marion. 2008. “MHC-correlated odour preferences in humans and the use of oral contraceptives.” Proceedings of the Royal Society B 275, 2715-2722. doi:10.1098/rspb.2008.0825

    (If you google for that doi, I believe you can pull up a PDF of the paper regardless of university affiliation, but I’m currently on a university network so I can’t swear to it.)

    Here’s a pull quote: “Our results therefore suggest that, at least in our sample, there was neither a significant general preference for MHC dissimilarity across normally cycling women, nor a significant preference for MHC similarity associated with pill use.”

    The effect reported in this article is a change in the relative preference for the smell of MHC-dissimilar men between a session when women were not on the pill, and a session three months later when they were. The effect is only statistically significant for white UK women reacting to white UK men’s smells (as smelled on a t-shirt) — and only if the t-shirt does not smell of deodorant, soap, cologne, or tobacco.

    The upshot, to me, is that showering probably has more effect on whether a woman is attracted to your smell than whether she’s on the pill.

    This has been your science nerd lecture for the day. (I am avoiding my Actual Scientific Work by reading scientific papers in other fields. Yes, I do this often.)

  23. i learned about this in my 9th grade biology class. that was in 1999. i feel like this knowledge has been around for a while… maybe just not well-known?

    after reading the article, i’m glad i have a non-hormonal IUD with my current boyfriend… i have a feeling that the pill, which i took for 5 years, messed me up with previous relationships.

  24. Caroline, I have been to four different doctors over the years and not a one ever has ever mentioned a connection to cancer.

    No my doctor didn’t technically “force” the pill, but she did write me a script after I said no thanks.

  25. The increase in cases of cancer is only an average. Women who have the genetic predisposition (one or both genetic markers) are much more affected. This is true with all hormone birth control treatments, but especially Depo Vera, the long lasting birth control shot.

    As a society we benefit much more from the ability for women to chose when and where they become pregnant. As a pharmacy student, I’m well aware that giving people facts without context is often much worse than leaving a patent in the dark. A much better approach would be: “Do you have a history of feminine cancer in your family?”

    The statement “The Birth Control Pill Increases Your Chances of Feminine Cancers” is misleading and given to an over-emotional response, as has been demonstrated by Purly.

    Fact: Feminine cancers are caused by complex interaction of risk factors.
    Fact: In almost all cases, the birth control pill has a risk so small as to be insignificant.

    A little knowledge is a dangerous thing.

  26. @UGLY CANUCK:

    So birth control pills will alter the normal course of human evolution, eh?

    Well, not really, since their whole purpose is to prevent passing on any of those changes to offspring.

  27. #26 – Hadn’t heard that it lowered some other cancers.

    #27 – How scary it is depends on family history. My ex gf’s grandmother and mother have both died from breast cancer, and apparently they weren’t the only ones.

    #35 – Actually, preventing offspring DOES alter the course of human evolution all by itself. But then, just about everything alters the course of human evolution. Hurray for chaos systems!

  28. @ #22
    according to my gynecologist, it actually DEcreases the possibility for breast-cancer…so I am confused, but am NOT coming off the pill. I did that 2 times and it always caused more problems than when on it.. which caused no problems whatsoever. I never felt any emotional changes on or off the pill..but it does mess up the menstrual cycle…amm..sorry men, I might have been a bit too open about this. :) but we are all intellectuals here, aren’t we? :)

  29. WHO takes any prescription without researching the risks and side effects? It amazes me that people pop pills (even aspirin) without bothering to look into what they’re ingesting. Jeebus. I knew about the risks of the bc pill when I was 15. That was 20 years ago, before the internet.

    There was a news story last night about women who had unnecessary hysterectomies because their doctors didn’t give them information about all their options. (Some cases the DOCTORS didn’t even know all the options) You better believe no one is taking my reproductive organs before I’ve exhausted all other options.

    And to get back to the story, I believe this. All the single women I know on the pill have really bad luck with men. Just anecdotal evidence, and a really small sample. But it makes me think…

  30. When you get the pill there is a little insert – telling you all the possible side fx, what to do if you screw up taking it, warnings – that you shouldn’t smoke while taking it – all that important stuff. It’s in every box. So please please everyone – don’t take medicine without reading the insert – also – ask you doctor and your pharmacist. Pharmacist are fantastic – they are the ones who actually have a degree in drugs.
    When I first went on the pill I talked to my doctor about the risks. We agreed that the risks that go along with unplanned pregnancy were worse. (being pregnant or an abortion are both higher risk than the pill)So I took it. Personally – I find my attraction to either sex is the same on or off the pill – but I find it kills my sex drive and flattens my emotions. It does make my periods less painful, my skin better and I get less bitchy though. For now I’d rather have my sex drive and all my emotions so I don’t take it.
    @ Anon 11
    Wow. Haven’t you ever noticed that you feel differently different times of the month? Isn’t that interesting? You are not just your mind. You are your body and all the hormones and chemical that go with it. It’s about understanding yourself. Have you never looked at a person and gone – “wow they are perfect for me – but they just don’t do it for me.”?

  31. IWood @12:

    I am pleased by the ever-increasing pile of evidence that “love” is a chemical reaction. It supports my deep, black cynicism and my rejection of romance as irrational monkey behavior.

    {sniff}

    i’m so lonely

    There, there, IWood. You’ll know it’s hit you when you find yourself sighing happily and saying “Yeah, but it’s really nice irrational monkey behavior.”

    Frogmarch @17: Peanut butter?

    JEFreivald @20, please don’t drag in unrelated political figures.

    Anonymous @25, a man who smells good when you go off the pill is a man who smells good. Hold out for the package deal that has the rest of the virtues included.

    PollyannaCowgirl @38, unnecessary hysterectomies used to be extremely common. I’d thought we’d left all that behind us until one day in the late 90s, when I came to a parting of the ways with my doctor after he suggested I “just have the whole thing out” on the grounds that at 42, I probably wasn’t looking to get pregnant. I’d had my suspicions before, but that was the moment when I knew the guy was seriously creepy. I didn’t make the obvious reply — “At your age, you’re not going to be having children either, so how’s about we cut off your balls?” — but I switched to a different practice.

    Less than two years later, he made headlines when he carved his initials three inches high in the abdominal wall of a patient undergoing a c-section delivery. (Links: 1, 2, 3, 4, 5.) I was so not surprised.

  32. Cheer up, Takuan. For all we know, he was eating his patients’ missing organs.

  33. PHEW! Thank g*d I have higher cognitive functions and can make decisions about choosing a life partner based on faculties other than sniffing. Gotta love humans.

    I have a doctorate in psychology, and this type of research really gets on my tits. “Men like women and women like men and we must procreate with the strongest hairiest man/smallest most docile woman in order to progress”. Well, if that’s progress…

    Yipee for the pill and reproductive control!

  34. Teresa @40:

    PBR = Pabst Blue Ribbon. I suppose it says something about my peer group that I thought that acronym would be universally understood. Though the peanut butter idea is a good one and probably worth researching.

  35. I went off the pill recently. Now I want to cheat on my BF! I’ve never been wanting to so badly before. I seriously consider it a lot and I’m very tempted around male friends. :(

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