Q&A with Dr. Robert Deaner, sex differences researcher

I believe that underlying biological differences is the main driver of the findings from this study. I'll try to avoid being sexist here.

Men are built better for running. Much better. So when you look at a group of 1000 men, you can find a decent number of them who have the basic biology for a high level of success at the sport. The bone structure (aka slender build), plus some aerobic ability.

For woman, things are more complicated. The right body type for running is much more rare. Very low body fat is rare in woman (and not always healthy), as is narrow hips and small breasts. Considered all together, I believe you'd have far fewer of the original 1000 who have the right skills to be fast.

As a result of variance in body type, one would expect more variance in performance, which would explain fewer close to the top.

were results consistent nationwide with Buffalo area races? Most will have more difficulties with the evolutionary explanations, which seem simplistic, than with the analysis of the data. The time slice is tiny and involves just the United States, right? Generalizations to all of humanity seem unwarranted. Statistics concerning math performances used to be used to show that women cannot do math (even when I was already in high school). Women were supposed to be unable to attain high education. Yet, today women constitute a significant majority of college students, graduate students, law students, medical students. So, women are competing with men in school and winning. Women are clearly extremely competitive with each other in many areas. Moreover, boys are pushed from day one to be competitive in sports. Virtually all of the national coverage of sports is about men's sports, except during the Olympics. Hence, current American sports have a gender bias. Opportunities are granted equally in running or even more to women at the college level now but there is far more focus on men excelling in sports and we all know that.

What evidence do you have that the differences are due to evolution?

Did you read the paper?

As I said earlier, 26 years during a time of rapid social change is not a "tiny" time slice.

I don't know whether our results are duplicated elsewhere in the US. There might be another long-term data set out there but if so I haven't heard of it. But in any case, jjjjjjj, the point is to have a consistently-gathered, rather comprehensive, long time series from the same geographical area. I'm sure I don't have to tell you that attitudes towards things like competitive sports vary widely across regions, not to mention the world. So one of the things you do in exploring things like this is to limit the variables if you can. Later they can be expanded, if it seems warranted.

Yes, of course all these anti-women things happened in the world, and for sure national coverage of sports is overwhelmingly male sports. I don't know how old you are, but I'm pushing 70 and I've seen it all unfold -- girls can't do that, etc. etc. When I first started running competitively (in the 1970s) it had only been a few years since women were disbarred from some of the Buffalo area races. So I've seen all this happen, firsthand.

But that's not really the point. The question is whether there are enduring M/F differences in competitiveness, or not. And if there are, what might cause them?

I'll cut and paste from the conclusion, and it should help you see the way that Rob and I have been thinking about all this.

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The final point is that the ultimate benefit of studying sex differences in enduring competitiveness is not to dogmatically support an essentialist position (e.g., “Men, but not women, compete.”) The payoff, instead, should be insight into the various factors that affect long-term achievement motivation. The current study only considered gender, but Deaner (2011) highlighted how achievement motivation should be affected by whether achievement in the domain yields relatively greater status or resources, and other studies taking an evolutionary perspective have shown how achievement motivation can be affected by the prioritizing of mating or parenting (Kanazawa, 2003; Farrelly and Nettle, 2007; see also Ceci and Williams, 2010). As research better characterizes sex differences in motivation and how these interact with environmental and social conditions, it should be possible to craft policies to better achieve desirable outcomes, including policies that provide men and women with genuinely equal achievement opportunities (Ceci and Williams, 2010).

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I'm assuming that you, and other readers, understand what an "essentialist position" is, and how it's routinely misused.

Your thinking is completely flawed if you think Darwinian evolution explains the persistence of genetically inherited traits in humans. The ability of humans to not only reflect upon our own existence, but also to influence the fitness of enormous groups of people--through things such as land development, public health, and medicine--fundamentally changes our relationship to the biological world.

Your assertion that people are ignorant if they think (Darwinian evolution) "magically doesn't apply to humans" is short-sighted and reflects your own ignorance of non-dominant fields of thought (which includes just about every field that does not rely exclusively on the scientific method).

How could you possibly think that human behavior is a product of the brain, as if it's a one way causal street? My favorite example of this is the kitten study. In this famous study, kittens were reared in environments with limited visual stimuli--for example, being exposed only to horizontal stripes. The visual cortexes of the kittens developed such that they were unable to see things that were not horizontal stripes. if the visual cortex is co-constituted with the environment, there's reason to believe that other areas of the brain are, as well.

Given this, it makes a great deal of sense that the gender differences so many people are apt to attribute to evolution and "the natural" are, in fact, differences co-constituted by a social world that clings to gender roles. Specifically, gender roles that encourage girls to be passive and boys to be aggressive and competitive. The last time I walked down the child toy aisles at Target, fifty years of rapid changes in gender roles and identities hadn't made much difference here.

If I wanted to give you a snarky answer, I'd say that all differences are due to evolution, in the largest sense.

But even though it's Letsrun's message boards, I won't.

Are you rejecting the entire notion that living things, including humans, are the products of evolution? If you are, then discussing it with you is pointless.

There's an enormous body of evidence from non-human animals that has to do with displays, sexual selection (both M and F) and the like. We have to ask, then, if human beings are exempt from this?

Or, as I'd put it (remember, I'm an anthropologist) are there cultural overlays, learned behaviors, that have the same effect? If so, do they have any genetic (speaking loosely) component, or not?

If there's no genetic component then we're not going to get very far down the evolutionary road. But if there is, then we can start to ask how it works (its function), what ultimately caused its existence (an evolutionary question). And we go from there.

If I were going to pursue this farther, as a research project (and I'm not going to), I'd build on this material by heading out to do standard anthropological participant-observation fieldwork. I'd spend a lot of time at races and I'd talk to a wide variety of racers. I'd get individual histories. I'd watch physical competition. I'd watch award ceremonies very carefully -- especially the runners who finished just out of the awards. You better believe I saw a lot of that in my years as a timer.

Basically, I'd see whether I could construct a convincing explanation -- based on evidence -- that didn't require innate psychological differences. If I could, then I'd argue that it wasn't evolutionary except in the largest sense (read Guppy's excellent comment).

I think I'd like a list of the fields that don't rely exclusively on the scientific method and yet are relevant here.

Don't confuse "our [changed] relationship to the biological world," which is a reasonable statement, with the way biological and cultural evolution work.

The idea that humans are beyond the reach of biological evolution, or are somehow above it, is not a new idea. People were talking about it in the 19th century and even when I was an undergraduate, but it's based on a flawed notion that some things are "biology" and others are "behavior" or "culture" and never the twain shall meet. In my experience (as a student and as a professor) people taking that position had always failed to understand the nature of culture (as it were) or the nature of biology.

It's pretty hard to imagine human behavior that's not the product of the brain. Surely you're not suggesting that cultural knowledge, behavioral strategies and the like are existing on some ethereal plane outside of the brain?

If you're suggesting that patterns in the brain can be laid down by instruction and observation, then you're saying something accurate but without explanatory value. It's obvious. It's not news. The very hard part is to go beyond the obvious.

Nobody gets out of anthropology grad school (or undergrad, I hope) without understanding that all kinds of gender roles and behavior patterns are learned. It's obvious.

The important question is: is that all? Does "learning" in the general sense account for everything we see human beings doing? Even as an anthropologist I can't accept that. It makes no sense to me, and it's not what I've seen while doing research. And it's not either/or. Human beings and their world are a whole lot more subtle than that.

As for Target's toy aisle, do you mean what you wrote? I interpret what you wrote as saying that fifty years of trying to convince boys not to be entirely and only boys (and the same for girls) hasn't had much effect. I shake my head when I see boy after boy heading for the trucks.

But don't you see that you're contradicting yourself? If the brain is somehow "co-constituted" (whatever that means) by the social world, then fifty years of rapid changes in gender roles appears to have had little effect. But if human beings are as you're asserting they are, it should have.

Do I misunderstand you? Say so, if I am.

Yes of course I know that living things evolve. I'm not an idiot. And I won't allow you to expand your definition of evolution to include social forces. There is a distinction. The paper argues that there are innate biological sex differences which arose out of evolution (in the strict sense). So let's stay on track.

I intentionally asked you a direct question, and it seems that you've given me your answer. You don't have any evidence that the differences are due to evolution. All of the differences that you observed could be attributed entirely to social influences that have nothing to do with how likely an individual is to pass on their genetic material.

Another problem I have with the study, and evolutionary psychology researchers in general, is that it fails to take proper care in considering how their unsupported conclusions and speculations will allow uneducated and bigoted individuals to propagate their regressive political agendas. I'm sure there are many letsrunners who read that headline and thought, "Yeah, that's what I've thought all along. Women just don't have it in them to be as competitive as men." I might even go so far as to say that careless speculation about genetic sex differences is unethical if you care about gender equality.

You ARE misinterpreting what I've written. I'm saying that gender roles have not changed that much over the past fifty years and that girls and boys are co-constituted by biology and a rigid gender system. I'm not surprised that boys rush to the trucks. I've seen many parents scoff when their boys show any inclination toward stereotypically feminine forms of play.

Equality before the law, which is what women in the United States have achieved (more or less) does not necessarily mean that many of the day-to-day practices that rearticulate gender differences have changed.

My primary assertion is that people are very quick to jump to biology and evolution and that most do not understand that biological development does not happen in a vacuum. Still, the author of the study being discussed here forecloses almost all other explanations of his findings and instead anchors his argument in evolutionary theory. This is not surprising, given that he is an evolutionary psychologist. The problem is that it oversimplifies phenomena that are incredibly complex and makes easy fodder for those who want to maintain social inequality by chalking things up to nature.

Finally, we can't ignore the fact that science is the most privileged form of knowledge production in the United States right now. This makes it all too easy for researchers and the public to look to positivist science to explain humans and society and turn a blind eye to less "scientific" disciplines. Hence Girls will be Girls' assertion that my logic in this argument comes from PC Women's Studies gobbygook.

get ugly xoxox! I read some of Deaner's work about 5 years ago in grad school, I hated it then and I hate it now. It's just like the scientific crap "caucasians" would spew to justify racism. I've been out of academia for a while now so I'm curious, is Deaner a respected researcher?

That has nothing to do with what I said. Changing our relationship to the natural world does not change our evolutionary history. The ability to reflect upon our own existence and to develop land and medicine is a product of our evolution. How is that relevant to anything I said? You sound like someone ranting about things you have no understanding of.

Pardon me for using science to explain the natural world. Again, you sound like someone who doesn't even understand the basics of science, let alone specific knowledge within various fields. Don't try to argue with science using non-scientific methods. No one wants to listen to your ramblings if not based on science.

You did not understand what I said, and you apparently don't understand that biology encompasses more than just genetics. I'm well aware of differential gene expression in response to different environmental stimuli, as are all biologists. You cite a study in which changes in kittens brains altered their behavior and use it as evidence that brains don't control behavior? Are you even reading what you're writing? You're correct in your last sentence though. Much of the brain is indeed plastic during development and even later in life. This is the whole basis of phantom limb syndrome, which you would have learned about in any neuroscience class, along with many other examples such as specific regions of the sensory cortex growing more in response to higher amounts of stimulation (say playing an instrument multiple hours a day for example).

You sound like someone who is completely unaware of every gender study published in every field from psychology to anthroplogy to physiology over the last 40 years. If you had even the most elementary knowledge of behavioral endocrinology or even cultural anthropology you would not say what you have. Why do you think toys haven't changed in the last fifty years? It's because our evolutionary biology for what boys and girls prefer to play with has not changed in that time. There've been many studies on this around the world. Even male monkeys prefer "boy" while female monkeys prefer "girl" toys. You might look up the story of David Reimer if you think everything is just environment.

People like you disgust me as I cannot believe anyone can be so ignorant of so much in this day and age. You're decades behind the times and apparently think your opinions are somehow greater than research in fields as diverse as behavioral ecology, psychology, anthropology, developmental biology, sociology, neuroendocrinology, etc, and your diarrhea of the mouth makes you look like one of the dumbest human beings alive. You can't make a boy act like a girl just by sticking a doll in his hand. You really think it's just coincidence that males' behavior changes when injected with male hormones? You might look up the organization-activation hypothesis... Good god, man, please go read a book.

Well, get ugly, I'm glad you know that living things evolve. You have to admit that your comment could be interpreted both ways.

You can claim you're not going to allow me to expand my definition of evolution to include social forces, but you'll be going it pretty much alone there.

Do you know what selective pressure is? If you do, do you think it must be only biological?

I have to tell you that even when I was in graduate school, back in the sixties, the notion that social forces easily set up important selective pressures wasn't a new idea. True, it seems to get forgotten and then "rediscovered," as it was a couple of years ago.

But it's well-established and not even difficult to understand. It's hardly a matter of expanding. No one who actually understands evolutionary theory would exclude social forces.

As Guppy says, please consult any modern evolutionary biology textbook.

Your point about taking proper care is a significant one, but I don't think the answer is not to publish work that can be misinterpreted. I do fault scholars who never get out there in public and explain what they're doing -- especially if it's something controversial. They should.

"Equality" all by itself is meaningless outside of mathematics. Equality always has a context, and I would argue that there's nothing in any specified gender "equality" that would fail on account of biological differences.

I knew an anthropologist who used to say something like, "What's important about [gender] differences isn't whether they exist or not, but whether they have anything to do with the the operation of a democracy."

litigiousness wrote:

get ugly xoxox! I read some of Deaner's work about 5 years ago in grad school, I hated it then and I hate it now. It's just like the scientific crap "caucasians" would spew to justify racism. I've been out of academia for a while now so I'm curious, is Deaner a respected researcher?

I couldn't tell you. I'm actually a statistician, which is funny because another poster claimed that I couldn't possibly know anything about uncertainty in scientific research.

I do have to admit that I was too vague in what I'm referring to as social forces. What I'm referring to are modern conceptions of how female athletes are perceived. My stance is that these social and cultural forces are much more likely to be the root of the differences that the author observed in the study. I'm talking about things like men being more encouraged to play sports than women from a young age. I'm talking about women being specifically discouraged from training at high intensity by doctors who tell them that it's unsafe for them not to get their period. I'm talking about women not being to train because of the desire to get pregnant--and furthermore that many don't believe that they can be competitive after pregnancy. There are two major running websites people go to for information, and one of them (letsrun.com) is full of misogynists. These are what I'm calling "social forces", and the list can go on and on.

It's interesting to me that as an argument tactic, you are trying to take what I'm calling social or cultural forces and incorporating them into your theory of the evolution of athletic sex differences. You keep telling people to read the paper. Well I did, and the only evolutionary claim the paper makes is that the sex differences are due to the male predisposition to competitiveness. It makes no claims about the social or cultural forces to which I'm referring, so trying to swallow them into the author's theory is dishonest.

Also, you keep trying to frame me as an uninformed pest, whether intentional or not, is another dirty argument tactic. While I admit that I was a bit vague with my language, you are far from correct on that front.

Are you inviting me to give you book recommendations, as well? If so, I recommend starting with something by Anne Fausto-Sterling. She is a biologist who has a lot to say about gender differences in biological research. The chapter on endocrinology is particularly insightful. I would also like to point you in the direction of "How Natives Think: About Captain Cook, For Example." Like Geertz in his response to Gananath Obeyesekere, I first thought your post was so logically flawed that it wasn't worth my time to respond to you. While you like to suggest that I know nothing about science, your post is rife with examples of scientific misunderstandings. Let's start with the premise that "our relationship to the natural world does not change our evolutionary history." It does precisely that. Human beings are now making explicit decisions (in some cases) about the genetic make-up of the population. This is important, of course, because it means that our behaviors are not reducible to drives, competitive or otherwise. Yet some evolutionary psychologists suggest that peoples' orientation to competitive running is more readily explained by these supposedly natural drives than by any of the proximal influences in their environment. The fact that I can reflect upon evolution itself allows me to engage in many behaviors that aren't attributable to my "natural" desire to pass on my genetic material. I can decide to put extra testosterone in my body. I can decide to have gender reassignment surgery. With that in mind, I would like to direct you to Kristen Schilt's work on transgender men. She had a sample size larger than n = 1, which is what your incredibly insightful (read sarcasm here) reference to David Reimer accomplishes. Most quantitatively oriented psychologists would tell you that an n of 1 does not give you much power to make inferences about human variation. I digress. Many of Schilt's informants decided to undergo gender transitions in adulthood, and not because they felt like they had been dealt a lousy hand by being born into the wrong kind of sexed body (though some did think this), but because they thought (correctly) that they could be something other than cis-gender. (Cis-gender involves living in the gender role that corresponds to one's birth sex). To continue, if I decided to put extra testosterone in my body, it would surely change the balance of my hypothyalamic pituitary gonadal axis, but I'm not sure how much it would change my personality and competitive drive or my desire to be a sub-elite road racer. I would still bring with me all of the cis-gender history of my past. On the other hand, I'm not sure there's a place for those with tenuous ties to dichotomous gender roles. Caster Semenya showed us that, though her case may be something more like androgen insensitivity syndrome. I remember learning about that in medical school, which I attended right after I spent the summer finishing up my undergraduate thesis in neuroscience. It wasn't until I made a career change and secured that fellowship in gender studies that I began to reflect more carefully on the role of epistemology in scientific research. I won't bore you with that, though. It's not very "scientific." Though I would recommend that you check out some stuff in the field of science studies.

thinking cap wrote:

While you like to suggest that I know nothing about science, your post is rife with examples of scientific misunderstandings. Let's start with the premise that "our relationship to the natural world does not change our evolutionary history." It does precisely that.

No, events in the present do not change what happened in the past. You are full blown retarded if you can't even understand that. The past 2.5 million years of our genus happened regardless of what we do today.

I've said multiple times that environment plays a significant role. You seem to fail to understand that if it weren't for your biology, you wouldn't be able to make choices at all, that evolution has selected for the ability to make decisions (and likewise be less inclined to make other decisions like chopping off your penis) and you still exhibit complete ignorance of how one's behavior is influenced by their physiology as well as basics of evolutionary theory, especially with your admittence of not knowing how extra testosterone would influence your behavior as the effects of extra testosterone are known even among the general public, let alone the scientific community. Also, one's behavior isn't dictated by their biology. I've not heard anyone even make such a claim in decades. Biology simply influences the probability of exhibiting a certain behavior. If you think probability of behavior is not inherited you should go back to high school and learn how natural selection works.

I've studied the biology and psychology of intersexuals to some degree and don't see how your reference to transgender men does anything for your argument. Quite the contrary, actually, as it is well understood how biology produces differences in sex, gender, and sexual orientation, particularly in males. But I'm sure since you remember learning about androgen insensitivity sydrome (partial AIS in the case of Castor Semenya) you're also familiar with the enzymes aromatase and 5-alpha-reductase and their critical role in sexual development of the genitalia and neurobiology of individuals as well as the biology of guevedoces and fafafini. If not, you should probably go review for a while.

I think we're in agreement that gender is a spectrum rather than two opposite poles though, which I don't understand where you got the idea I was opposed to that view as it's well accepted (and has been for quite some time) within the fields which study gender biology and psychology and I never made any claims against such a position.

I'll take a look at the books you mentioned, thanks. I would recommend you have a look at any text available on evolutionary biology as you've demonstrated many times now you have a terrible understanding of it.

Intersexuals and transgender men are not the same population. Also, it is not well understood how biology produces differences in sex, gender, and sexual orientation. Our current constructs of sexual orientation date back only about 100 years or so. One of the major flaws of the kind of "evolutionary" research you talk about it that it uses historically recent constructs as if they are relatively enduring human traits or as if they flow seamlessly from the biological function of humans. I presume you're referring to work by J. Michael Bailey, who in addition to having flawed study designs with little power to make any inferences about men in America, much less men across the world, violated human subjects research ethics in pretty egregious ways. We're not in agreement about the gender continuum with two opposite poles. I have a great understanding of human biology. The difference with me is that I don't pretend that I can and should write my contextually-bound understanding into research as if it's objective fact. It's useless to argue with you, though, because you've made up your mind without looking at the evidence.

Thanks everyone for the interest and your patience – a family emergency arose yesterday so I’ve been unable to respond until now.

I’ll try to address some of the issues that were raised. Thanks to Guppy and Don (runtime) and other who have made similar points.

Here goes:

Some people expressed deep skepticism of using evolutionary theory to understand human behavior. I obviously disagree, but I don’t think I can convince true skeptics, especially in a post like this. So I’ll mostly leave it alone. For those who are truly interested in understanding evolutionary approaches to human behavior and why the oft-repeated critiques are generally incorrect, I’d be glad to provide reading suggestions, but this is a good place to start:

http://www.psych.ucsb.edu/research/cep/primer.html

Some wondered why any evolutionary or biological explanation is necessary to explain the patterns. In other words, couldn’t various socialization forces alone account for everything we found in this and previous studies? Logically, yes they could. In fact, almost any well-developed theory (or ideology) will be sufficiently flexible to “account” for anything. But the key to good science is developing and testing falsifiable predictions. So imagine I had discussed this issue with people around 1980. I would explain that males participate in distance running 4x more than females and that there are 6x more males running relatively fast. Then I asked people to imagine that the participation differences and financial incentives favoring males would completely disappear by the late 1990s. Would the socialization hypothesis and its proponents predict that the number of relatively fast performers would disappear or at least become very small by 2011? It certainly would. Now some might object that “testing this prediction” in this way isn’t fair since I don’t have anyone on the record saying precisely this. But this isn’t a good objection because there are many scholars who have said this about sports in general in the U.S., i.e. the sex differences in sports interest and motivation have disappeared or soon will. (Btw there isn’t much (any?) data suggesting this is true.) So, for anyone who is keeping score fairly, the distance running results that we have documented over the past 30 years must count against a pure socialization hypothesis.

But some have argued that eliminating sex differences in participation opportunities and incentives isn’t nearly enough. In other words, we need to eliminate all kinds of socialization differences for boys and girls, and we have a very long way to go on this. I have three responses. First, this may be true but this is contrary to what the Supreme Court believes which holds that making changes in school sports via Title IX will be sufficient. Second, this may be true, but it doesn’t contradict an evolutionary account which holds that socialization practices will often (but not always) complement biological mechanisms. (If you find it surprising that an evolutionary approach to understanding behavior hold that environmental factors are important, then you aren’t up to speed on evolutionary psychology or evolutionary biology.) Third, there is apparently very little strong evidence that socialization contributes to sex differences in sports interest and motivation. Many scholars in sports science would be scandalized that I say this because they believe it so strongly. But most (all?) of their evidence is easily open to other interpretations. For instance, showing that children, especially boys, who say they like sports more also are much more likely to be signed up to play organized sports is consistent with a socialization hypothesis. However, it’s also consistent with a simpler account that parents respond to their children’s inborn interests. My students and I are still reviewing the relevant evidence on this so I’m not entirely confident about it yet. And again, I’m not saying that socialization doesn’t matter, only that there is apparently very little strong empirical evidence that it does. In his book, The Blank Slate, Steven Pinker has made very similar points about developmental psychology in general. We (most scientists and the public) believe our socializaion hypothesis so strongly that we haven't bothered to test it against alternatives.

So what do we know contributes to sex differences in sports interest? Sports interest seems to be part of a general package of boy-typical behavior. And we know that much of this is caused by processes that occur prior to birth, especially the effects of androgens on the brain. For instance, dozens of studies have shown that girls with the disease congenital adrenal hyperplasia (CAH) are exposed to abnormally high levels and their interests and behavioral styles are much more boy typical than control girls. Three studies have shown that CAH girls have unusually high levels of sports interests, especially for masculine sports. There are many other lines of evidence for the importance of prenatal hormones, including David Reimer and more than a dozen similar cases. Sheri Berenbaum and Adrian Belz have recently published a review of all the relevant kinds of evidence, and I’d be happy to email it to anyone who needs access. By the way, if you doubt this prenatal androgen research because someone told you it was unconvincing, then your source probably hasn’t consulted the empirical evidence in the past 10 or 15 years. Again, I'm not saying that all sex differences are caused by prenatal hormones, only that it is definitely known to contribute. Other things must matter too.

Asfadsfsda suggests that more males have the underlying biology (skeletal features, aerobic capacity) necessary to be good runners. This is a viable and important hypothesis. I hope that someone will gather data to test it. Part of the reason I am trying to publicize these results is to stimulate a research group to gather some relevant skeletal data (I do know the relevant aerobic data pretty well, though, and it doesn’t support this hypothesis.) I’m not testing this hypothesis myself because no matter what I do, nobody will find it convincing. For instance, imagine I hypothesize, based on relevant literature, that narrow hips are necessary for excellent running. Then if I find that similar numbers of men and women in the population have this trait, people will dismiss this finding and say that hip width wasn’t the crucial trait; it was something else I haven’t looked at. It might even be difficult to publish this “negative” result.

That’s all I’ve got time for now. Thanks again for your interest and thoughts.

Let’s keep it civil.

Rob Deaner

Rob and Don,

I enjoyed the paper. I think the conclusion could be taken even further--and Rob alluded to this--to say that enduring competitiveness in distance running is a function of androgen levels rather than male gender (a good proxy for androgen levels). It would, of course, be difficult to get a large enough population of CAH and AIS runners to prove this.

I don't understand how people get so bent out of shape when a study empirically proves something that everyone knows to be true in the first place. Men are generally more competitive than women and women are generally more nurturing than men. There is nothing more apparent in life, yet people construct complex, nonsensical arguments to convince themselves this isn't the case. Figuring out the cause of this dissonance would be a good anthropological study. Why is this something people don't want to believe? What advantage does one gain by having this sort of cognitive bias?