Does the Taste of Semen Have Evolutionary Roots?

By Melissa Lafsky | April 21, 2009 11:50 am

MilkJerry Coyne—author and renowned evolutionistthinks so:

It is the conventional wisdom in human sexuality that semen tastes bad. Anyone with minimal sexual experience knows that although many women will perform fellatio on their partners, most bridle at the thought of swallowing the ejaculate. Its flavor is frequently characterized as revoltingly bitter or salty. The “swallow or spit” dilemma faces any woman who performs such an act, and whose partner regards swallowing as a gesture of love…

Why does semen taste so foul? One answer, of course, is that the chemicals necessary to make an ejaculate effective have the side effect of tasting bad. Semen is only about 5% sperm, with the remainder of the fluid consisting of a complex mixture of compounds from the prostate gland and seminal vesicle…

But this proximate answer will not satisfy the diligent evolutionary psychologist. After all, natural selection could presumably add some sugars or good-tasting stuff to semen if it were advantageous to do so. Why does it not do so?

A moment’s reflection gives the answer.

Natural selection maintains the repugnant taste of semen so that a man’s sperm will wind up in the appropriate place: the vagina and not the stomach. So long as sperm tastes bad, women will not be tempted to swallow it, but will turn their male partner towards conventional intercourse, which of course is the only act that will produce children.

Well, there you have it! Now all we need is a way to test this hypothesis. Volunteers?

Disco: Love Potion Number 10: Oxytocin Spray Said to Increase Attraction
Disco: What Viagra? New Spray Increases Male Performance Time
Disco: Men, Beware! Sketchy Sexual Performance Drugs Prove Fatal

Image: iStockphoto [not actual semen]

MORE ABOUT: evolution, men, sex
  • Finkleman

    Count me in!

  • Francisco

    I disagree, from my experiences I find semen to be quite delicious…

  • OP

    I have tasted the semen from both of these guys, and I think Francisco’s is better tasting than Finkleman’s

  • humor critic


  • Jay

    This is not science. This is crap.

  • Jon B

    Drinking pineapple juice beforehand gets rid of the funky flavor, or so I’m told.

  • Pheadrus

    if you change your diet(more veggies and fruits, fewer red meats(pork, deer, beef), cut out the dairy(cheese, milk, and yogurts)) semen ends up tasting sweet with only a slight tanginess. i have tasted my own and my girlfriend agrees.

  • Cosmic Stargoat

    I hope no women read this crap. Tastes foul? Boy, that really going to help things out for guys trying to get….ahem…ahead. May a thousand incontinent camels visit your tent at night Mr. Coyne.

  • Dave

    Very disappointing read. I won’t act like I wasn’t slightly entertained, but that’s not the sort of entertainment I seek from Discover.

    “Natural selection maintains the repugnant taste of semen so that a man’s sperm will wind up in the appropriate place: the vagina and not the stomach. So long as sperm tastes bad, women will not be tempted to swallow it, but will turn their male partner towards conventional intercourse, which of course is the only act that will produce children.”

    Do you have your very own jump to conclusions mat? You’re making some big leaps there. I don’t know if this is meant to be humorous or what, but I’ll go to the onion for that. This is garbage. Does Discover actually monitor this blog?

  • Catch22

    If anything, it would seem like the opposite would be the case. Because swallowing does not increase chances of conception, there has been no evolutionary pressure to encourage that behavior (make it taste better).

  • Christina Viering

    So the official excuse is, “Sorry, I can’t, it’s bad for evolution”.

  • jon

    that Coyne has got to be the biggest douchbag ever…what an idiot. This post is an insult to humans everywhere.

    Hey… Jerry….why have fags been selected?…what’s the evolutionary advantage of eating feces?

  • Pat

    The logic behind this texte is flawed because if a perosn actually had seman that tasted lets say like chocolate milk trust me he would get a lot of women and eventually would proceed to vaginal intercorse eventually.

  • Stacy

    It says right in the text that it is a hypothesis – this is what scientist do – hypothesize about ideas and try to find the best and most accepted solution. Also, how cum nobody can spel anymore?

  • off-ended

    I’ll agree with Jay, this IS a load of crap.

  • off-ended

    I agree with Jay, this IS a load of crap.

  • off-ended


  • Kelyn

    hmm…just had this conversation with my bf. I really do not know where the ‘conventional wisdom in human sexuality that semen tastes bad’ came from. Was there a survey done? The reaction to swallowing has more to do with the slime yuck factor than taste. And some women are not grossed out by it at all, and some just don’t do oral anything..again…the yuk factor.

    All guys taste different; some taste good (sweeter), some get the ‘never doing that again!’ reaction (bitter). This seems to have influenced my enthusiasm for performing the act, and enthusiasm for continuing to have wonderful elaborate sex with the guy. In fact, I know plenty of women that enjoy this intimate act of fellatio. I seriously doubt this has anything to do with natural selection towards putting sperm where it will go fertilize. Anyone with a good healthy sex life knows that oral sex is not a substitute for intercourse, and that if you are regularly doing oral, you’re also likely having good ole missionary, head-banging penetration–thus leading to potential fertilization. Did I get carried away…apologies. Coyne started it.

  • Pingback: links for 2009-04-25 « Unisyc.()

  • girlie

    I thought this article was ok. It brought a lot of questions to my mind that I will talk to my boyfriend about. I think that more studies should be done but I believe that whoever wants to do it will and everyone has different taste. Its really a matter of if you like it or not.

  • lauren

    All of the people saying “omg, dis guy is so stupid lol”, are stupid. I mean, he didn’t present it in the best way possible, but he has a point. I do agree with the comments saying that not all semen tastes bad, but in general semen is supposed to taste pretty bad.
    When he’s talking about evoloutionary reasons, you have to put it in the context of primitive humans, not modern society. I personally do not think semen tastes bad so that humans won’t perform felatio instead of intercourse, considering that probably very few of the pre-civilization humans even thought up the idea of inserting a penis in to any other slot than the one it was intended for. My personal hypothesis is that semen tastes how it does because of diet, and the natural fluids it consists of.

    You probably understood none of that.
    don’t bother insulting me because I will never visit this page again and i won’t have the petty argument you expect of me.

  • Don

    Are you saying that, at one point in time, semen actually tasted GOOD?!

    DANGIT! I knew I was born in the wrong era!

  • firstmate

    TOTAL CRAPOLA! This is unsubstantiated garbage with no evidence. I have tasted my own from the lips of my wife. A bit bland but not as nice as the fragrance of her own juice.

    Why failures like this poster expose their sad inadequacies is beyond me.

    Sweet dreams all.

  • Wabbit


    DON’T eat tuna before…

    DO eat pineapple.

    Problem solved.

  • Woody

    Diet, I understand from my partner, does effect taste; notably, asparagus, parsley, and other herbs. By the way; this did not stop us from having two children.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


Quirky, funny, and surprising science news from the edge of the known universe.

See More

Collapse bottom bar