I call BS (but I could be wrong)
April 22, 2013 12:10 PM   Subscribe

Is there any biological evidence for the assertion that female sexuality is more fluid than male sexuality? Or is this imbalance more likely due to cultural factors?

By 'fluid sexuality', I mean 'more likely willing to be sexual with people of both genders.' This could either mean bisexuality or just a willingness to experiment with people who don't necessarily align with your sexual orientation.

I'll go ahead and display my bias here: I have always assumed that, to the extent that women in my (middle-class American) culture have more fluid sexuality than men in that culture, that it is more or less entirely due to cultural factors and not to some inherent biological difference between men and women. I assume that in a different cultural context, men could be seen to have a more fluid sexuality than women, or the same level of fluidity.

But many people seem to believe that this is not the case, and that women are just naturally more inclined to sexual fluidity than men are.

So what's the evidence say? I want to be convinced either way.
posted by showbiz_liz to Science & Nature (16 answers total) 11 users marked this as a favorite

The version I've heard (which may or may not be the current scientific consensus) is that an MRI of a gay man's brain has certain structures that appear more similar to that of a straight woman than a straight man. There's apparently no correlation between the brains of lesbians and straight men, however.
posted by Oktober at 12:19 PM on April 22, 2013

Disclaimer: this is all based on a single course in human sexuality that I took just over 20 years ago. Although, it was a very, very good class.

I would wager that cultural conditioning is more akin to what's the case here, but may also contribute to being willing to admit to that experimentation as well contributing to the willingness to experiment in the first place. One of the things that Kinsey found in his research is that in reality, we're all kind of fluid - rather than things being a binary "straight or gay or in the middle" thing, we're all kind of at different points on a continuum. However, that continuum is running smack bang into an equally complicated set of societal expectations about gender and sex.

And - for a variety of reasons - those societal expectations are a little more tolerant of women having same-sex encounters than they are of men having same-sex encounters. Granted, some of that framing is coming from porn for straight guys (think about it a sec, incidentally - isn't the fact that so much porn for guys features "lesbian women" narratives a little bit strange?), but two guys gettin' it on somehow socially gets more flack than two women doing so. So - with that mindset kind of circulating out there in the ether, that means it's more likely that a woman who's a little curious about trying a same-sex thing would end up saying "okay, lemme try, why not" and it is more likely that a guy who's curious would think, "mmm, not worth the hassle, ultimately, so no". Even though each of these hypothetical people could be at exactly the same place on the Kinsey continuum - the stakes are just higher for the guy if he tries to experiment than they are for the woman.

I'm actually curious, though, whether the spike in slash fanfiction that's taken place over the past 20 years would do anything to affect that, ultimately - because when the fanfiction writers and readers (who are almost all straight women) explain the appeal, their reasoning sounds almost exactly like the appeal straight guys have for "girl on girl" type of porn. So I'm wondering if in enough time, that kind of societal narrative could change.
posted by EmpressCallipygos at 12:31 PM on April 22, 2013 [2 favorites]

I'm also skeptical, but there is some evidence out there. See Anne Fausto-Sterling in Sex/Gender: Biology in a Social World and her discussion of Lisa Diamond's work. AFS is excellent on this stuff in general: she's a biologist with a good grasp of gender studies as well. This is a deeply contested field of study, though, so take all claims you see with heapings of salt.
posted by col_pogo at 12:33 PM on April 22, 2013 [2 favorites]

My guess after taking a lot of college courses on sexuality and gender (including some around the time this "women's sexuality is more fluid" research was coming out) is that we just can't know whether that's a nature or a culture thing.

The studies I have read that allege that bisexuality is more common in women all used MRI's and I believe some kind of genital monitoring on women and men who were exposed to arousing imagery of various types. That kind of study doesn't actually tell us much about bisexuality as a biological phenomenon, despite the fact that it's usually interpreted that way in the media.

We just can't untangle sexuality, desire, identity, biology, and culture cleanly enough to thoroughly test for things like this, unfortunately.

(Keep in mind, too, that the brain is a malleable organ. Any study that alleges Women Are Like This and Men Are Like That because MRIs is, well, it might not be a bad study, but it is probably not really saying what the media thinks it's saying.)
posted by Sara C. at 12:35 PM on April 22, 2013 [1 favorite]

We might look at the past - what about societies where it was pretty normal for many men (a far greater percentage than are considered "gay" in contemporary terms) to have same-sex relations? Obviously, ancient Greece, also samurai Japan, also sailors, also the great British public schools, also various tribal societies through history. (As far as I know, women in ancient Greece were discouraged from same-sex relationships, for that matter.)

And for that matter, what about kinds of sexuality that are not recognized in the post-colonial west? There are many societies (I'm thinking Phillipines and Thailand off the top of my head) where people assigned male at birth might "live as women" or live as a gender that is not "man" or "woman" - and those people would mostly have sexual relationships with men, and depending on the society this might be as normal as heterosexuality. These genders were often prohibited - and often with violence - under colonialism, and their social role changed, often as I understand it became more marginal and discriminated against, but that's not how it always was. (If anything, as far as I know there are many more ways for people from non-Western or indigenous societies assigned male at birth to live "as women" or as a different gender than for women to live "as men" or as another gender.)

This is why I am skeptical of the "part of the brain lights up, therefore it is an inherent human trope" school of brain research.
posted by Frowner at 12:39 PM on April 22, 2013 [2 favorites]

I find the biopsych stuff pretty unconvincing, personally, as I'm not sure — even if there is some difference between "gay brain" and "lesbian brain" that you can distinguish on an fMRI — how you'd ascertain with any confidence that it wasn't culturally influenced. After all, there are lots of high-level processes that can affect an fMRI, so the fact that it's a heavily culturally influenced behavior wouldn't rule out it having some physical signs, and it wouldn't necessarily imply that those physical traits are causative.

Also, I think there is a strong confirmation bias in some quarters towards a very reductionist, everything-is-physical (or worse, everything-is-genetic among some evopsych fans) approach to sexuality that doesn't adequately account for the wide and varied range of sexual expression across cultures, and it's worth always being suspicious of results that seem to neatly confirm preconceived notions.

So with that said, I've always thought that EmpressCallipygos' point probably sums up why there are, or appear to be, more women willing to experiment with women than there are men willing to experiment with men: the social risk for a man who experiments with another man is extremely high. Society is seemingly a whole lot less threatened by expressions of female sexuality than male sexuality.

There was a segment recently (within the past few months at least) on the Savage Love podcast where Savage talked at length about the large number of "how do I know if my boyfriend is actually gay" questions, relative to the small number of "how do I know if my girlfriend is actually a lesbian" questions. Setting aside what you might think about D.S., the volume of questions alone is interesting.
posted by Kadin2048 at 12:55 PM on April 22, 2013 [1 favorite]

This discussion of MRIs is a bit of a derail, although I fully agree with all the critiques of sweeping claims based on small-sample scan studies. Some of the other evidence out there is experimental, ethnographic or otherwise qualitative (my own preferences). L. Diamond's work is apparently longitudinal and interview-based.
posted by col_pogo at 12:57 PM on April 22, 2013 [1 favorite]

I find the biopsych stuff pretty unconvincing, personally, as I'm not sure — even if there is some difference between "gay brain" and "lesbian brain" that you can distinguish on an fMRI — how you'd ascertain with any confidence that it wasn't culturally influenced.

Even sillier, the MRI quoted above was comparing "gay brain" to "straight woman brain". It strikes me, though, that the way you'd test that is "show the subject erotic pictures of people of both genders and see which they react to." So it would be picking up that both the straight women and the gay men are "similar" in that they respond to the erotic photos of men, presumably.

But that doesn't necessarily prove that the "gay male brain has similar structure to a straight woman's brain," it only proves that "gay men and straight women think pictures of men are erotic," and...uh, I think we kind of figured that.

And that's not even getting into the possibility that some people may prefer a particular erotic photo because they are able to project themselves upon the subject of the photo -- for instance, a woman may dig an erotic photo of another woman masturbating - but it may be because she is a straight woman and is imagining herself as that woman, and not because of any "fluid sexuality" thing. Meanwhile, a photo of a guy masturbating may leave this same woman cold. Even the porn we look at isn't necessarily binary.

So if that's how they're measuring the MRIs - "here, look at these pictures and we'll record which ones you respond to" -- that is an imperfect science right there.
posted by EmpressCallipygos at 1:11 PM on April 22, 2013 [1 favorite]

Do you have any evidence for the idea that women who don't identify as lesbians are more likely to have sex with other women than are men who don't identify as gay to have sex with other men? Because I actually think there's a lot of cultural assumption that straight women have lesbian experiences, but men who are really straight would never have sex with another dude. And I don't know of any evidence to prove that's true.

So I think that before you ask whether the "imbalance" is nature or nurture, you have to ask whether there actually is an imbalance in the first place. Because I think it's very likely that men who identify as straight are engaging in sex acts with other men without telling anyone (or at least, without telling sociologists), while women who identify as straight are more likely to tell others about past experiences with other women. But the fact that women talk about it more doesn't mean that women are doing it more.
posted by decathecting at 1:16 PM on April 22, 2013 [1 favorite]

A guy named Baumeister studies this: Erotic Plasticity

I gravitate towards sociobiology, but many people (scientists) consider it speculative woowoo. Could be. Don't really care. Your question seems relevant to Baumeister's stuff, so there it is.
posted by FauxScot at 1:34 PM on April 22, 2013

The problem with the "biology versus culture" question is that there is no way to separate out the two. Culture shapes the environment in which we're born and grow up, and environment shapes which genes are expressed and how strongly, which hormones are produced and in what proportions, which pathogens we're exposed to and so on...with the result that culture becomes literally written into our bodies along with our genes. Most everything about ourselves - our brain activity, our personality, our behavior, our susceptibility to certain diseases - is based on a complex interaction between biology and environment in which both play a crucial role.

Think of it this way. Suppose you have a person who is genetically susceptible to lung cancer. If they never smoke, they probably won't get cancer because their lungs will be exposed to few carcinogens. But if they do take up smoking and get sick, which is responsible for their cancer: their genes, or the culture that created cigarettes? The answer of course is both.

Now if you're trying to study lung cancer and smoking, you can compare populations of smokers and nonsmokers and plausibly draw some conclusions. But you can't compare populations of culturally-shaped and not-culturally shaped to figure out if bisexuality is biological or cultural, because the second does not exist. You can do cross-cultural studies and kind of guess that if there's a lot of variation around a certain type of behavior cultural influences more likely predominate, but you can't even look at certain behaviors running in families as evidence their might be a genetic link, because family is also our single strongest source of cultural transmission.

So to return to your original question, about all I'd feel comfortable saying is that:
a) there's a pile of evidence - much mentioned above - that the degree of public fluidity of sexual expression has varied a great deal both in time and across cultures for men and women

b) that sexual activity is almost invariably subject to a great number of cultural rules, prohibitions and controls such that it is dangerous to assume that public expression matches private expression, let alone underlying desires

c) that it is impossible given our current state of knowledge to rule out biological differences in the sexual fluidity of men versus women

d) and in fact it is certain that there is somewhere a genetic component to sexual expression, and would be highly surprising if it were not somehow sex-linked

e) but that anyone using the words "women are just naturally more inclined" to describe pretty much anything related to sex and sexuality is either speaking very imprecisely or has not thought very deeply about the question at hand.

tl;dr Rather than be convinced either way, actually you should probably remain agnostic.
posted by psycheslamp at 1:43 PM on April 22, 2013 [10 favorites]

Evidence, although not the biological kind: According to wikipedia, The Janus Report on Sexual Behavior (1993) found that 5 percent of men but only 3 percent of women consider themselves bisexual.
posted by emilyw at 3:12 PM on April 22, 2013

Emily Nagoski has some really good discussion about sexual fluidity on her blog, The Dirty Normal. This is her original post about sexual fluidity in women, but this one addresses some of the possible biological factors a little more explicitly. (The TL;DR is that, as of 2010 when she wrote that post, the research was inconclusive.)

Should go without saying, but her blog is generally NSFW, although it doesn't have many images -- just lots and lots of discussion of sex.
posted by linettasky at 4:04 PM on April 22, 2013

Lisa Diamond's very readable Sexual Fluidity: Understanding Women's Love and Desire is all about this.
posted by Lieber Frau at 10:24 PM on April 22, 2013

I would second reading Baumeister's work. He is a very highly regarded and productive social psychologist.
posted by Silvertree at 8:03 AM on April 23, 2013

This question does not have a scientifically satisfying answer. Feel free to say or believe whatever you want.
posted by zscore at 9:48 AM on April 23, 2013

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