Ideology trumps science once again: Daphna Joel and Cordelia Fine deny the notion of “male vs. female brains”

Cordelia Fine, a professor of the history and philosophy of science at the University of Melbourne, has carved out a niche for herself by attacking the notion that there are any evolved and genetically-based differences between males and females. Her books have been best-sellers (Testosterone Rex won the Royal Society book prize), probably because her conclusions appeal to those of a certain ideology. But those conclusions are flawed (see here, for instance). Fine’s critiques of some studies purporting to show sex differences are often good, but they’re combined with misguided characterizations of other work as well as the ignoring of results that go against her men-and-women-are-pretty-much-the-same thesis. In other words, Fine is tendentious, not objective, and her claims must always be taken with a grain of salt.

This is all on view in her op-ed with Daphna Joel (a professor of psychology and neuroscience at Tel Aviv University) in Monday’s New York Times (click on screenshot below).

If you accept that, on average, males and females differ in how they behave, what they think, and how they feel, then there are only two reasons for this: there are evolved differences, or those differences come about when “no difference” brains are differentially conditioned by society. It is, however, ridiculous to deny that there are evolutionary differences between the sexes to at least some of human behaviors, including sexual behavior. And any differences, be they cultural, genetic, or a combination of both factors, must be instantiated by a difference in brain structure, even if we don’t yet have the tools to see those differences. After all, behaviors and preferences come from the brain. So what are Joel and Fine talking about?

It turns out that their article is slippery in two ways. First, it conflates average differences between the sexes in behavior, emotions, and mentation with whether an individual can be diagnosed as male or female. So while Joel and Fine admit (grudgingly) that there are differences between men and women in both brain structure and behavior, they harp relentlessly on whether a single person can, from inspecting that individual’s behaviors and brain, be put neatly into the “male” or “female” class. Actually (see below), we’re already close to that.

But that’s a bogus problem, for the general claim about male/female differences rests on averages, not whether an individual can be diagnosed with 100% accuracy. Read this passage of their op-ed for some weasel-words, for instance:

The key point here is that although there are sex differences in brain and behavior [JAC: note the admission], when you move away from group-level differences in single features and focus at the level of the individual brain or person, you find that the differences, regardless of their origins, usually “mix up” rather than “add up.” (The reason for this mixing-up of characteristics is that the genetic and hormonal effects of sex on brain and behavior depend on, and interact with, many other factors.) This yields many types of brain and behavior, which neither fall into a “male” and a “female” type, nor line up tidily along a male-female continuum. Even when you home in on only two psychological characteristics, people don’t fall in line on a continuum from, say, extreme systemizer or “things-oriented” — supposedly the “male” pole — to extreme empathizer or “people-oriented”— the “female” pole. Rather, as recent studies have shown, people’s self-reported tendency to empathize tells you almost nothing about their self-reported tendency to systemize, and people may be highly oriented toward both things and people, to mainly one of these, or to neither.

The notion of fundamentally female and male brains or natures is a misconception. Brains and behavior are the product of the combined, continuous interactions of innumerable causal influences, that include, but go well beyond, sex-linked factors.

Note the word “fundamentally” here, which is a strawman claim that few people would embrace: the claim that every person’s brains and behaviors slot them neatly and diagnostically into either a “male versus female” binary. The questions that most researchers ask, however, is whether there are average differences in behavior and brains, and, if so, how large are those differences.

We all know that there are average height differences between men and women, with men being about 7-9% taller than women in nearly every country in the world, yet you can’t tell from the height of a single individual whether it was male or female. I’m a short male (5 feet 8 inches), and there are plenty of women taller than I.  I could claim, as do Joel and Fine, that “the notion of fundamentally female and male heights is a misconception,” and I’d be right. But that would be missing the real difference, which is hugely significant and, of course, raises scientific questions: why is there that difference? Is it the result of natural selection, and, if so, what kind? And of course if you combine height with other traits, like genitals and chromosomes, you get close to 100% diagnosability.

Likewise with Joel and Fine. By conflating average differences—which could be substantial, and important in explaining, say, male versus female preferences and differences in sexual behavior—with diagnosability of single individuals, they are somehow conveying the message that there aren’t differences between men and women’s brains and behavior. They are blank slate-ists, and they know what they’re doing. But they’re doing it for the wrong reasons: their motivation seems to be that the admission of some differences between men and women’s brains and behaviors will somehow justify sexism. This becomes clear at the end when they describe their social program (my emphasis in the passage below):

The claim that science tells us that the possibility of greater merging of gender roles is unlikely because of “natural” differences between the sexes, focuses on average sex differences in the population — often in combination with the implicit assumption that whatever we think men are “more” of, is what is most valuable for male-dominated roles. (Why else would organizations offer confidence workshops for women, rather than modesty training for men?) But the world is inhabited by individuals whose unique mosaics of characteristics can’t be predicted on the basis of their sex. So let’s keep working on overcoming gender stereotypes, bias, discrimination, and structural barriers before concluding that sex, despite being a poor guide to our brains and psychological characteristics, is a strong determinant of social structure.

But some day we may be able to tell one’s sex with substantial accuracy by looking at one’s brain, either in vivo or in vitro. And who could argue that of course we should try to overcome gender stereotypes, bias, discrimination, and so on? Who doesn’t want equal opportunity for people of different genders and ethnicities? But Fine and Joel seem to be telling us as well to simply stop looking for average differences.  

Joel and Fine’s tendentious piece reminds me of those people who deny genetic differences between ethnic groups because there are not single diagnostic differences that can tell you your ancestry. But their are small differences among many genes, and taking them all together you can discern someone’s genetic background with remarkable accuracy. Yes, you can’t diagnose someone’s ethnicity from one or two traits or genes, but you can do so with groups of genes. And, I think, once we have a better handle on brain structure, and can combine different aspects of brain function and morphology, we’ll be able to do that with brains. It’s interesting that the motivation for the genetic blank slaters is the same as that of people like Joel and Fine: they think that if we see differences, especially genetic ones, it will somehow justify racism and sexism. As I’ve said before, it needn’t do that, for we should not base moral equality on biology.

My second plaint is about the science they cite. Now I haven’t checked all their scientific claims in this article, but I did check one. It’s this one:

In 2015, one of us, Daphna Joel, led an analysis of four large data sets of brain scans, and found that the sex differences you see overall between men’s and women’s brains aren’t neatly and consistently seen in individual brains. In other words, humans generally don’t have brains with mostly or exclusively “female-typical” features or “male-typical” features. Instead, what’s most common in both females and males are brains with “mosaics” of features, some of them more common in males and some more common in females.

Daphna Joel and colleagues then applied the same kind of analysis to large data sets of psychological variables, to ask: Do sex differences in personality characteristics, attitudes, preferences, and behaviors add up in a consistent way to create two types of humans, each with its own set of psychological features? The answer, again, was no: As for brain structure, the differences created mosaics of feminine and masculine personality traits, attitudes, interests, and behaviors. For example, in the data set on 4,860 adolescents from the National Longitudinal Study of Adolescent Health, the variables on which young women and men differed the most included worry about weight, depression, delinquency, impulsivity, gambling, involvement in housework, engagement in sports, and a femininity score. So far, so gender normative. But: Not a single person had only feminine or only masculine scores on these variables. Rather, what was typical of both men and women (70 percent of them, to be exact) was a mosaic of feminine and masculine characteristics.
Here’s the paper at issue (click on screenshot to see it):

Yet on the same page of Proc. Nat. Acad. Sci. where their article appears, there is a note that there are four rebuttals to the paper of Joel et al.:

This article has a reply. Please see:

Multivariate revisit to “sex beyond the genitalia”

Yes, there is a female and a male brain: Morphology versus functionality

Patterns in the human brain mosaic discriminate males from females

Joel et al.’s method systematically fails to detect large, consistent sex differences

The titles more or less tell you what’s going on: multivariate analyses are actually quite good at discriminating male and female brains into two groups. (I can’t find a reply by Joel et al. to these critiques, but one may exist.) Joel and Fine do not mention these credible criticisms of their paper; they just pretend that their statement stands clear and unrefuted. I find that a sleazy way to behave, and had I vetted the editorial for the NYT, I would have insisted that Joel and Fine at least point it out.

So be it. We needn’t base our morality on our biology, but we needn’t base our facts on our ideology, either.

 

UPDATE:  Bill Boecklen (comment #13) wanted to post this figure to illustrate his point, but neither of us know how to post figures. Below is what he said and his figure:

I suspect the Fine-Joel argument may result, in part, from a mathematical artifact – the projection of a multidimensional space onto a line. The line, of course, is the male-female continuum. The multidimensional space represents all the characters that distinguish males from females. The observation that an individual cannot be assigned into male or female categories with probability =1.0 does not in any way suggest that there are not non-overlapping categories in n-space. Consider the following graph of two non-overlapping groups in 2-space. A projection onto either axis will result in overlapping categories in 1-space:

h/t: Cesar

50 Comments

  1. rickflick
    Posted December 7, 2018 at 2:08 pm | Permalink

    I read the article earlier today and was disappointed to see they don’t allow comments. As a subscriber to the NYT, I expected to be able to voice and opinion. But, not so.

    • Christopher
      Posted December 7, 2018 at 2:23 pm | Permalink

      If the NY Times wants your opinion, they’ll give it to you!

      • Posted December 7, 2018 at 4:04 pm | Permalink

        In Soviet Amerika, article comments on you.

      • rickflick
        Posted December 7, 2018 at 7:56 pm | Permalink

        😎

    • dd
      Posted December 7, 2018 at 6:41 pm | Permalink

      More and more, NYTimes does not allow comments on articles dealing with identity issues.

      Pay attention to that, and see if your experience is the same as mine.

  2. Posted December 7, 2018 at 2:19 pm | Permalink

    The paper they cite is in stark contradiction to another paper I saw, that said that the brains of transgendered youth matches the brain patterns of their expressed gender.

    https://www.sciencedaily.com/releases/2018/05/180524112351.htm

    Saying that there are no ‘male’ or ‘female’ brains implicitly asserts there is no transgender brain. I would haul out the popcorn if someone accuses Fine of being a TERF.

    • Posted December 7, 2018 at 2:43 pm | Permalink

      I’d be curious to see if some conversion therapy activists do not seize Fine’s arguments as support for their agenda.

    • Kelly
      Posted December 7, 2018 at 2:56 pm | Permalink

      I managed to get myself banned from an extreme far left website for going down that particular rabbit hole.

      How can gender identity be both a social construct and an innate identity?

      How can gender identity be innate, such that trans people will commit suicide if not permitted to live their lives according to their identity, yet also a social construct such that there are no sexes and no differences between male and female?

      What is the basis of gender identity? Is it just a subjective feeling that comes out of the ether, or is there objective evidence for this feeling in the architecture of the brain?

      I was banned for ‘asking too many questions’

      • TD2000
        Posted December 7, 2018 at 4:07 pm | Permalink

        Very well said. I would perhaps go further and question the need for the concept of “gender” in the first place. One’s sex doesn’t just determine anatomy: it includes behaviors and psychology. So why come up with the concept of “gender,” which is, as you said, just a “subjective feeling that comes out of the ether.”

        • Kelly
          Posted December 7, 2018 at 4:21 pm | Permalink

          Would the concept of gender identity even exist without biological sex?

          If biological sex is a social construct, then gender identity would have to be so as well.

      • Heather Hastie
        Posted December 7, 2018 at 6:28 pm | Permalink

        Being banned for asking too many questions says a lot more about the person doing the banning than the person being banned!

        It reminds me of extremist religions (e.g. Seventh Day Adventists) or extreme political systems(e.g. North Korea, Soviet Russia, Maoist China) where they limit or prevent exposure to other viewpoints to maintain belief in their ideology.

    • Posted December 8, 2018 at 2:48 pm | Permalink

      My thoughts exactly. Either there are male and female brains or transgender is a social construct.

  3. Posted December 7, 2018 at 2:24 pm | Permalink

    “… strong determinate of social structure”

    Are we arguing over the definition of strong determinate. As in whether the difference is significant due to sex or genetics.

  4. Diana MacPherson
    Posted December 7, 2018 at 2:42 pm | Permalink

    All I know is that every test I take makes me a strong systematizer and the last one I took put my empathy at average overall but low for females and average for males. I suddenly realized why I’ve always enjoyed the company of males more than females (even in childhood) even though I do all the girly things.

    • Saul Sorrell-Till
      Posted December 7, 2018 at 2:57 pm | Permalink

      You enjoy the company of males because you’re hardwired to seek out the alpha male and mate with him. Your cotton candy woman brain is focused on one thing only: the immediate co-option of a male soul and its retention as a life partner and strong He-Man like protector. You use the ‘shrew-like nagging module’ of the female brain to grind him down and eventually break him so that he is good partner material. Then once you’re bored of him you immediately begin scanning the horizon for the next alpha male into whom you can sink your succubus fangs.

      I’ve been reading a lot of Jordan Peterson and other deeply credible conservative thinkers recently you see, and I thought you could do with having your own psychological urges explained for you by a strong, capable, reasonable man. You’re welcome!

      • Diana MacPherson
        Posted December 7, 2018 at 3:21 pm | Permalink

        😂 Sadly, I’ve read and heard these words written/said unironically.

        • Saul Sorrell-Till
          Posted December 7, 2018 at 3:33 pm | Permalink

          I don’t doubt it. I’ve heard it plenty of times myself.

      • Diane G
        Posted December 8, 2018 at 4:04 am | Permalink

        Literally LOL! This is going to keep me smiling all day…

    • infiniteimprobabilit
      Posted December 7, 2018 at 5:41 pm | Permalink

      Your toilet-paper-orientation preferences would seem to contradict that, as this highly scientific and authoritative article states.
      https://www.maxim.com/news/toilet-paper-direction-2016-4
      (‘Under’ = ‘feminine’.)

      However, your practice of changing the orientation apparently counts the other way, towards ‘dominant’.

      Who needs shrinks when we have toilet paper?

      cr

      • Diana MacPherson
        Posted December 7, 2018 at 5:56 pm | Permalink

        I chalk it up to one of the “girly” things I do – wear jewelry and make up & orient the toilet paper a certain way.

        • rickflick
          Posted December 7, 2018 at 7:14 pm | Permalink

          That last one certainly reflects brain structure. I often ask myself, is my brain over or under?

      • Posted December 8, 2018 at 2:55 pm | Permalink

        What does it say about me if my attitude is “I don’t give a toss about which way the toilet paper is oriented, as long as there is some”?

  5. Saul Sorrell-Till
    Posted December 7, 2018 at 2:48 pm | Permalink

    I agree that political motivations should remain separate from scientific concerns.

    However, I disagree that the notion of ‘fundamentally female and male brains’ is a strawman position that the writers of the article have invented out of whole cloth.

    It’s a strawman only in the same way that Sophisticated Theologians say that creationism is a strawman. ‘Sure millions of people believe it, but they don’t count because they’ve got it wrong’
    …But they do count. The kind of deterministic, black and white thinking about male and female brains to which the article alludes might not be widespread among scientific professionals, but neither is creationism.

    There’s a reason they bring it up in the article: they haven’t just magicked up a talking point that no-one uses. Plenty of people talk about female and male brains being fundamentally different; it’s a right-wing shibboleth, and it has come up in practically every political debate I’ve ever had about women in business/sport/politics/etc.

    • rickflick
      Posted December 7, 2018 at 11:19 pm | Permalink

      Then perhaps the article should have been written as – We propose to argue against the kind of deterministic, black and white thinking that some, especially creationist-types espouse. And, they could have left out all the gibberish about research suggesting total uniformity. No, I think you’re defending the indefensible.

      • Saul Sorrell-Till
        Posted December 8, 2018 at 7:53 am | Permalink

        “they could have left out all the gibberish about research suggesting total uniformity.”

        Where in the article did they say that? That’s a proper strawman.

        “Then perhaps the article should have been written as – We propose to argue against the kind of deterministic, black and white thinking that some, especially creationist-types espouse.”

        It seems to me that that’s exactly what they were doing.

        • Don Anon
          Posted December 9, 2018 at 12:56 am | Permalink

          Dude, the NYT doesn’t waste page space debunking creationism, and it logically wouldn’t waste page space debunking the idea that “man” and “woman” are black-and-white categories. Moreover, if it did, you’d think it would address the pertinent research debunking the arguments made in its pages.

          It’s pretty obvious what’s going on here, sorry to tell you. Cordelia Fine tilts at strawmen and the NYT cheers her on.

  6. Davide Spinello
    Posted December 7, 2018 at 3:25 pm | Permalink

    I agree that political motivations should remain separate from scientific concerns.

    Also

    There’s a reason they bring it up in the article: they haven’t just magicked up a talking point that no-one uses. Plenty of people talk about female and male brains being fundamentally different; it’s a right-wing shibboleth, and it has come up in practically every political debate I’ve ever had about women in business/sport/politics/etc.

    Which one? Who are this people? Should we let “people” dictate the scientific debate, and have scientists lie for jesus (or social justice) so that those people/right wingers/nazis don’t have a talking point anymore?

    By the way, I have heard plenty of (competent) people taking the time to explain the difference between a statistical moment of a distribution and an element of the population to which the distribution refers. At some point we have to accept that buffoons of different colors will appropriate and distort science for their own ideological ends. I just wish that those buffoons wouldn’t be the scientists themselves.

    P.S.: I HATE THE RIGHT I HATE PETERSON AND AND I HATE QUILLETTE

    • Davide Spinello
      Posted December 7, 2018 at 3:26 pm | Permalink

      Sorry, this was a reply to comment 5.

    • Saul Sorrell-Till
      Posted December 7, 2018 at 3:32 pm | Permalink

      That was a long response to an argument I didn’t make, an argument I made a point of preemptively addressing in the first paragraph of my comment.

      The rest of your lysergic post…I’ve no idea what it means.

  7. Posted December 7, 2018 at 3:27 pm | Permalink

    Reblogged this on The Logical Place.

  8. Scott
    Posted December 7, 2018 at 3:31 pm | Permalink

    I want to share a few links about a comment by Alan Sokal on another NYTImes piece that also was unblanced in presentation and slippery in its wording about the subject.

    Alan Sokal:

    https://physics.nyu.edu/faculty/sokal/comment_on_NYT_latour.html

    Commentary, by Andrew Gelman, on the Sokal comment, here:
    https://andrewgelman.com/2018/12/07/40828/

    I can’t brain today so I’ll say no more.

    Hope the articles are enjoyed.

    • Steve Pollard
      Posted December 7, 2018 at 4:21 pm | Permalink

      Yes, very interesting; thanks for drawing our attention to those articles. I found Gelman’s defence of Latour to be most unconvincing. Latour comes across to me as a complete charlatan, who understands very little of science, and misrepresents what he does understand. His position as one of Sokal and Bricmont’s prize pseuds is secure!

      • Scott
        Posted December 8, 2018 at 4:04 pm | Permalink

        Thanks for the reply and I’m glad the articles were of interest.

        what sticks with me are quotes about interpretations actng “… different ways: as an assertion that is true but relatively banal, or as one that is radical but manifestly false.”

        The overall inability of any audience distinguish between such disparate interpretations seems in part to be the basis of our societys “post truther-isms”.

        cheers,
        S

      • Posted December 11, 2018 at 11:54 am | Permalink

        Latour has only one redeeming virtue – realizing, after a long time, that the powerful can use postmodernist nonsense to do their thing.

  9. Posted December 7, 2018 at 4:03 pm | Permalink

    As Saul Sorrell-Till suggests, I don’t see them as battling scientists so much as attitudes held by the general public. Talk about the male and female brains being structurally different is common. It is used to explain all kinds of things. It’s not just the right wing either. We have half the world saying that male and female brains are identical and that differences in outcomes are socially and culturally determined, while the other half says male and female brains are structurally different and using that to explain every difference in behavior. I am sure that sometimes these two ideas are held by a single person!

    The authors may have committed some offenses here, and they may have an unfounded axe to grind, but they do get it right in their conclusion where they stress that conclusions reached based on the average male/female should not be applied to individuals.

    I also have a bone to pick with the concluding there are differences in brain structure due to difference in behavior. Sure, sometimes we can conclude that there must be differences between two brains but “brain structure” makes it sound like more than can be safely assumed. It’s not as if an individual who likes sports develops an extra brain lobe. Even when we do see anatomical differences between male and female brains, we don’t know if it’s the cause of the different observed behavior.

    • Posted December 7, 2018 at 4:10 pm | Permalink

      Unless you’re going to invoke spandrels, physical sex differences in brains must yield some manifestation.

    • Steve Gerrard
      Posted December 8, 2018 at 12:56 am | Permalink

      If brain structure means anatomy, that might be too strong a term. But big differences can occur just from different sensitivities to various stimuli, for instance. The effect some hormone has on the stimulation of the hippocampus by the amygdala is not an anatomical feature per se, but it is a physical property of the brain. It could initially depend on sex; it could also change as a result of aging. It’s a huge maze of possibilities.

    • Saul Sorrell-Till
      Posted December 8, 2018 at 8:03 am | Permalink

      ” I don’t see them as battling scientists so much as attitudes held by the general public.”

      This is what I was trying to say, only you’ve summed it up in a single sentence.

      I see it as well-intentioned but flawed. Not massively so however, and certainly not “indefensible” or “gibberish” as other commenters have claimed. Things are almost always more complicated than that, to paraphrase Ben Goldacre.

  10. Posted December 7, 2018 at 4:06 pm | Permalink

    Not sure why scientists are wasting their time doing research, when it’s been decided that there are no male or female brains. Except for transgenders, who have the opposite-sexed brain.

    Now stop asking awkward questions or I’ll report you.

  11. TD2000
    Posted December 7, 2018 at 4:13 pm | Permalink

    Dr Coyne:

    Excellent post.

    I’ve said it before and I’ll say it again: please write a book on this topic! You’re one of the few academics on the Left that is informed and cogent enough to make these arguments. Plus, you’re retired, so have no need for self-censorship.

    Please!

    • Posted December 7, 2018 at 4:19 pm | Permalink

      Agree.

    • dd
      Posted December 7, 2018 at 6:44 pm | Permalink

      I too agree

    • Posted December 7, 2018 at 9:25 pm | Permalink

      I’d buy that book.

      -Ryan

  12. BJ
    Posted December 7, 2018 at 4:29 pm | Permalink

    Aside from all the studies done that have demonstrated significant differences between men and women at the biological/psychological/neurological level, there is another great piece of evidence that makes it very hard to deny that these differences come down to social conditioning: the more egalitarian a society, the more men and women differ in things like hobbies, career choices, etc. For example, the most egalitarian societies have the greatest differentiation average career choices between men and women. The freer women are to make their own choices without pressure from society, the more their outcomes are differentiated from those of men (on average).

  13. William Boecklen
    Posted December 7, 2018 at 4:41 pm | Permalink

    I suspect the Fine-Joel argument may result, in part, from a mathematical artifact – the projection of a multidimensional space onto a line. The line, of course, is the male-female continuum. The multidimensional space represents all the characters that distinguish males from females. The observation that an individual cannot be assigned into male or female categories with probability =1.0 does not in any way suggest that there are not non-overlapping categories in n-space. In fact, every character taken individually may have overlapping distributions and yet collectively they can describe non-overlapping categories.

    From Jerry: I’ve added a figure showing Bill’s point to the end of the post above. (It’s Bill’s figure but neither of us know how to post figures.) See above!

  14. William Stewart
    Posted December 7, 2018 at 4:42 pm | Permalink

    See Gregory Cochran’s review of both Fine’s and Joel’s claims at West Hunter. Also reviews by Stuart Ritchie at Quillete(sp?).
    Also Larry Cahill’s article at Cerebrum.
    Also the large study coauthored by Ritchie (sample size > 5000) that found many differences between male and female brains. There is also an article reporting differences in the connectome of men and women. You can probably find the article by googling. Sorry for the sketchy comment, but all of the above references do exist.

    • rickflick
      Posted December 7, 2018 at 6:29 pm | Permalink

      Thanks for the references. I especially like the way Cochran uses sarcasm:
      “what could explain men’s huge strength advantage? Eating Wheaties?”
      I couldn’t find the Ritchie piece though. When I go to Quillette I only see, “Do Parents Make a Difference? A Public Debate in London”.

  15. chris
    Posted December 7, 2018 at 6:41 pm | Permalink

    Daphne Joel wrote this paper several years ago in which she ‘concluded’ that brains were both male and female based on some measurement (I forget the details) which changed under different conditions (maybe stress?) such that under non-stress conditions male and female brains appeared different while under stress conditions the measurement in the female brain now resembled the measurement in the male brain under non-stress conditions. It was all gobblydegook.

  16. Diane G
    Posted December 8, 2018 at 4:19 am | Permalink

    sub

  17. Torbjörn Larsson
    Posted December 9, 2018 at 5:44 pm | Permalink

    But their are small differences among many genes, and taking them all together you can discern someone’s genetic background with remarkable accuracy. Yes, you can’t diagnose someone’s ethnicity from one or two traits or genes, but you can do so with groups of genes.

    Though if you insist on aggregating diagnostic features, what you end up as dominating is not ethnicity but locale (due to marriage customs): https://www.nature.com/articles/nature07331 .


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