Gender Bender: How do you tell a man from a woman?

Gender Bender: How do you tell a man from a woman? The International Olympic Committee has decided to use testosterone levels to decide who can compete as a woman. But it’s not that simple: testosterone levels of elite athletes, both male and female, spread out over a range and overlap as seen in this scatter plot:

• Besides, there are no studies showing that athletes with higher testosterone compete better in sports. Neither is there evidence that response to hormone is the same between individuals. An extreme case is complete androgen insensitivity syndrome. These individuals are chromosomally XY, the normal makeup for men, but their bodies don’t respond to testosterone. So they develop female genitals, but have testes, not ovaries.  South African powerhouse runner Caster Semenya is thought to be one such person. She was banned from competing and then, mysteriously, brought back this year ( 

• Half a century ago, the IOC subjected women athletes to “nude parades” before a panel of judges. After realizing that outward appearance can be confounding (as a result of adrenal gland abnormality, for example), they tested for Barr bodies, characteristic of XX chromosomes. But females can have a single X chromosome. This was followed by testing for the SRY gene thought to determine male gender (See my Men! Why U So SRY? post But the Atlanta Olympics revealed 8 female athletes who carried this gene, all of whom were eventually allowed to complete.

• Naturally high testosterone in women is a genetic trait, no different from having more efficient muscles or acromegaly (tallness). So why should some athletes be penalized for this particular trait? Clearly, the goal is to prevent unfair advantage in sports. But it’s complicated….


#london2012 #scienceeveryday  

This entry was posted in Rajini Rao and tagged , . Bookmark the permalink.

75 Responses to Gender Bender: How do you tell a man from a woman?

  1. … Screw genders, have people compete by weight class instead.

  2. Rajini Rao says:

    Gert Sønderby , interesting idea! Have to think about that one.

  3. Jim Preis says:

    Change the default uniform to the women’s beach volleyball uniform.  It should be obvious from there.

  4. Jim Preis I recommend reading the fine article right above 😉

    “Half a century ago, the IOC subjected women athletes to “nude parades” before a panel of judges. After realizing that outward appearance can be confounding (as a result of adrenal gland abnormality, for example), they tested for […]”

  5. Rajini Rao says:

    Except that XY individuals can look like women! There is an interesting observation re. photographing women’s volley ball..more booty shots than seen in swimming, for example.

  6. Let the phases of the games be unisex! 

  7. Andrew Hunter We could always subdivide by testosterone class 🙂

    I’m actually only half-kidding. It would presumably address quite a few doping issues, too. And we’re de-facto already doing that by splitting into men & women, so might as well go a bit more fine-grained.

  8. Rajini Rao says:

    Andrew Hunter , good point. Shah Auckburaully , I read somewhere how the Williams sisters were thoroughly trounced by a 203rd seeded male player in a friendly competition..and they all agreed that it was due to gender differences in strength. So unisex wouldn’t work I’m afraid 😦

  9. Chad Haney says:

    Interesting this topic came up in Bearman Cartoons post.
    Here’s a refresher on what happened to Floyd Landis during the Tour de France.

  10. There are no easy answers in the changing way modern societies regard gender (and how some older civilizations used to, before things like monotheistic cultures came in).  Whatever the IOC does, I’d hope it’d be in the most respectful way possible.  But profit-driven bureaucracy and respect aren’t generally things that go together.

  11. Andrew Hunter IIRC, testosterone testing is not that expensive.

    But in reality, this test will be fraught with problems, too. IIRC women are actually more sensitive to testosterone levels, absorption rates differ, etc. etc. 

    I’m just saying that if the IOC already uses it as the default “you’re a woman” test, we might as well go all the way. 

  12. Rajini Rao says:

    Thanks for the science blog, Chad Haney ! Checking it out now.

    Yeah, my Chinese friends on FB were hopping mad about this article in Nature, of all journals, about the swimmer Ye Shiwen. Take a look at the comments:

  13. Just make the whole thing unisex and turn the Olympics into the Hunger Games. 

    In all seriousness, unless the above mentioned tests are performed at birth for all humans, there is no point in forcing them onto people later considering they may have led different lives as to the lives they could have led had they been made away of their true gender since early childhood.

  14. Rajini Rao says:

    The writer in Slate would agree with you, Shah Auckburaully . The idea is that people who live as women, legally, should be allowed to compete as such, no matter what their testosterone levels.

  15. Difficult topic. Somehow or other I think we want to try to be fair to “typical” women, who might otherwise find themselves unable to compete in many events.  

  16. Chad Haney says:

    I think the Nature article brings out an interesting point, i.e., blood profiling can “flag” a sample as having an anomaly and hopefully future methods can identify the anomaly. EPO was used as an example.

  17. Rajini Rao says:

    Stone Bryson , because weight for weight, androgens build more muscle mass 🙂 That’s why some people abuse steroid hormones.

  18. Kalua J.K says:

    Wow since when did it become so comlicated to tell the difference between men and women, very interesting article Ms. Rajini thank you for the share.


  19. Rajini Rao says:

    Hehe, who knew indeed, Kiele J.K ? You and I must clearly be women if only because we subject ourselves to the torture of high heels 😉

  20. Not hijack your post Rajini Rao I’m going to share and start a side question of that is quite divergent to the discussion happening here: 

    Why not create events specifically designed to evaluate the physiological advantages females have over males rather than, forcing females to compete in events designed to evaluate the inherent advantages males have over females ?”

    All the great comments here really got me thinking, so thanks to all who contributed!

  21. Kalua J.K says:

    Lol! Yes love the torture of heels purely for sheer vanity of it lol. However one could argue that there are men who love the torture of heels. I have seen it myself many times in San Fran there were times I had to admit they rocked the stilettos better than I do. Lol.

  22. Rajini Rao says:

    Thanks for the idea, Christopher Vallo ! Any suggestions?

    Of course, mental athletics would obviate the need for muscles and testosterone 🙂

    Earlier today, a bunch of us of Indian origin were bemoaning the fact that our home country of one billion has only managed one bronze and one silver so far (in rifle shooting, something that requires no physical strength). On the other hand, pretty much every spelling bee or science fair competition has excellent representation from India 😛

  23. Andrew Hunter The issue, I think, is that the Olympics try to externally impose a view of what gender is. At the same point, for quite a few people, gender is what they define themselves as (cf. the “gender queer” movement)

    I’m not convinced we’ll ever be able to sort that out to an extent that will make everybody happy. 

    And the Slate idea that Rajini Rao mentioned, letting people compete as the gender they live as, won’t solve the issue either. I know quite a few hyper-competitive individuals who’d gladly live their lives as women if it meant a) winning the Olympics, and b) collecting the associated sponsorship deals.

    As usual, money is the true root of all evil 😉

  24. Rajini Rao I suggest you take up rifle shooting and come back to us about the “no physical strength” part 🙂

    Sure, it requires much less than e.g. weight lifting, but it’s not insignificant, either. 

    But we’re already struggling to define “gender” here – let’s not extend it to defining “sport” 🙂

  25. Jay Gischer says:

    Interesting discussion.   I’m fascinated by how men have a much bigger spread for testosterone levels than women, even among athletes.

    I think testosterone levels are quite clearly affected by external conditions.   All humans testosterone levels raise in anticipation of having sex.    POWs came back from Vietnam with extremely low levels of testosterone – reproduction wasn’t the issue for them, survival was.

    I think it’s quite likely that there are other external factors that can affect testosterone levels, in addition to the one’s I’ve mentioned.   So dividing competitors up by testosterone level is kind of a problem, even leaving doping out of it.

  26. Rajini Rao says:

    Haha, I probably can’t be trusted with a rifle 🙂 Rachel Blum  You know, I had changed that phrase from my original “probably does not require as much physical strength”..Fail!

  27. Chad Haney says:

    Rachel Blum reminds me of my favorite sport, Formula One. Some even say it isn’t a sport, until they try the training regimen of the best drivers. They do special weight training to build up their neck muscles to handle the G-forces from accelerating, braking, and taking corners at high speed. It also reminds me of when people see the movie stars shoot a pistol with one hand. There are YouTube videos of people smacking their skull with a pistol because they can’t handle the recoil.

  28. Rajini Rao says:

    Jay Gischer , thanks for reminding us that testosterone (or any hormone) levels can change depending on the environment and stress levels. Although, I would have thought that war increased testosterone due to survival demands and violence associated with warfare. I found this interesting article on social competition and testosterone levels:

  29. “Do it by weight classifications, and let the best human win…”

    And be forced to tell our talented, athletic daughters that they can forget about competing at x y & z sports at a high level.  

  30. Rajini Rao says:

    It will all be moot on 12-21-2012, eh Stone Bryson ? 😀

  31. Chad Haney says:

    Don’t forget leap year.

  32. Jay Gischer says:

    Most of what I understand about T comes from this book, which is very interesting, even though I don’t quite agree with everything the authors say:

  33. Jay Gischer You’re completely right – the spread is impossible.

    The main issue is that we have something that glorifies winning a genetic lottery – and then we try to compensate for the fact that not everybody gets dealt the same hand.

    It’ll always be unfair to some extent. And since there’s a strong incentive to cheating, any “fair” regulation will be abused to cheat. 

    It’s a losing battle, but it’s a fun way to pass time 🙂

  34. Rajini Rao says:

    Also, it’s only a matter of time before testing before exams becomes commonplace. Think of the complication in distinguishing between prescription drug users and abusers.

  35. I did a semester at Sophia University in Tokyo back in 2006, where I had occasion to chat with a Harvard undergrad. She told me that a very high percentage of kids at Harvard were using Adderall during midterms and finals — “nearly everyone I know,” she said.  Thing is, it works. 

  36. Rajini Rao says:

    Yeah, I bet it does, Christopher Carr . A good friend, my age, surprised me the other day by saying that she took Adderall and that it really helped her focus and get her work done and grants written. Whoa. Of course it did. I’m just not sure she needed it. I’ve wondered why that’s not academic doping.

  37. Dextroamphetamine/ amphetamine is a hell of a drug.


    Improves _everyone’s_ concentration (at certain doses), not just ADD/ADHD-diagnosed persons. 

  38. Prior to Adderall people took Inderal to help with Anxiety and focusing for exams, but only for a very short time. I wonder too about the academic doping.

  39. Rajini Rao says:

    Cheryl Ann MacDonald  There are nice parallels between competing in sports and academics. The difference is that there are  no real gender differences in actual performance (IMO), although there may well be in methods of learning, and such 🙂

  40. It would have to be a very narrow and peculiar sort of academic competition to tease out the small statistical differences in male and female cognition — e.g., some sort of 3D object array position recollection task (where women appear to have a small advantage, statistically speaking). 

  41. Whoah!  Never saw that term.  It would explain why, when I close my eyes, it is so easy for me to find a “photo on file” rather than just think where it is in words.  I can take mental photographs that can stay for, er, decades.  I could still call to mind images that were “taken” when I was only 8.  Or am I on the wrong track here and you’re talking about something entirely different?

  42. Object location memory in complex 3D arrangements of things, is what I’m referring to.

    There have been a number of studies; here’s one:

  43. Uh-oh.  I don’t think I’d do very well at that one…

    Thank you for sharing!  =^_^=

  44. That’s ok — I’m not great at rotating 3D objects in my head. 🙂 

  45. Rajini Rao says:

    I loathe 3D spatial tasks..can’t even estimate how much space I would need in a suitcase or frying pan 😛

    I love pattern recognition though..especially as it applies to words and letters.

  46. Rajini Rao says:

    Have not found it yet, J.F. Sebastian , although I did get a laugh from the summary of this research: The males of two bipedal hominid species that roamed the South African savannah more than a million years ago were stay-at-home kind of guys when compared to the gadabout gals, says a new high-tech study led by the University of Colorado Boulder.

    Read more at:

  47. Rajini Rao says:

    Prehistory may hold surprising and heartening secrets if we could only figure out time travel. Women were equal to men as recently as the Vedic times in ancient India, until the Law of Manu sent them into a decline.

  48. Rajini Rao says:

    Thank you, J.F. Sebastian ! I could probably Google around and find if I did not get side tracked by interesting links as much:)

  49. Testosterone levels in a Female athlete might be higher than some very normal men also!

  50. but cool scatter plot Rajini Rao 

  51. Rajini Rao why not compete by average ability, rather than gender? Your posts are the best, by the way.

  52. Rajini Rao says:

    Thanks, Mike McLoughlin . I think I know what you mean re. sorting athletes by ability. By analogy, in school, students are sorted by math ability to classes that are on grade level,  below grade level or above (one, two or even three years ahead of grade). Within each level, students are more or less equivalent, but some are better than others.

    So what is important is not so much whether you are male or female, but rather your average performance level. Sure, at the very top category of running or swimming, there may only be males but at different levels the genders would be mixed. Does that make sense?

  53. Chad Haney says:

    People will sandbag like the badminton episode.

  54. Well, Chad Haney I would say the cure for that is the same: disqualification.

  55. Exactly, Rajini Rao – it seems eminently more sensible.

  56. Rajini Rao says:

    Chad Haney , that’s a good point. But, I would counter the sandbagging argument (badminton example) with the academic analogy again. In school, the harder the course, the more valued one’s grade. It is well known that colleges look more favorably at a harder slate of courses (even if a few B’s are mixed in with A’s) than straight A’s in low level/easy classes. Perhaps prestige could be factored into the difficulty level in sports too. They must already do this for team sports, no?

  57. Chad Haney says:

    In a sports analogy, let’s take a weight lifter. You know your average weight you can lift. For any competition leading up to the olympics, you sandbag. You’ll always be put in a class below your capability and you’ll get top score (A’s, in your analogy). You stay in that weight class for the olympics and easily get gold when you lift at your true capacity. I don’t see where the harder vs. easy weight lifting comes in based on your hard vs. easy course load. I think this is why it’s a bad idea to group athletes by performance alone. I think you are suggesting, using the weight lifting analogy, that a weight lifter would be classified by, maybe, the ratio of their weight vs. what they can lift or something more than just what they can lift.

  58. Rajini Rao says:

    Yes, the weight lifter in the lighter weight category wins a lower ranked and less prestigious medal. The same as the student getting an A in an on-grade level math is not as big a deal as the one who gets an A in math 2 grades above. In fact, GPA in schools is weighed by the difficulty level of the course. You can have both weighted and unweighted GPA. Competitive college entrance is known to be biased to the former. Not much different from the weight lifting analogy.

    This argument is just an “academic” exercise, of course- it’s not likely to happen in the world of sports, but it is the standard in school 😉

  59. Chad Haney says:

    Thanks for the link Feisal Kamil ESPN does something similar for hockey but I don’t think the NHL uses it. Relative Power Index.

  60. Concerning testosterone:

    I wasted lots precious time, yesterday, trying to reason with a vulture, who, in her own tagline was a “very bright, highly opinionated yet completely honest woman”,- whose honesty and “science” showed that I (and my testosterone) were personally responsible for raping, beating and abusing women all over the world. I’ve always loved challenges and gymnastics  but this shot-putting overlap was beyond me. 

  61. Rajini Rao says:

    I have no idea who this is? Sorry about the experience, John Condliffe .

  62. Rajini Rao Don’t worry,I will never be an easy whipping-boy for tea-bagging rabied ranters). I may be a magnet, but have yet to be encircled.

     I think there’s something in my profile that keeps them at bay.

  63. Feisal Kamil   Sorry you missed the sparks flying in Buddhini’s post yesterday. 

  64. Chad Haney says:

    Feisal Kamil blocked and deleted, so don’t bother looking, if I remember right.

  65. Chad Haney says:

    sorry, here

    I had a go-around with the same person and she circled me afterwards.

  66. Chad Haney She’s out there, encircling, and biding her time…

  67. Kalua J.K says:

    John Condliffe sorry to hear about your very negative experience with this person. I’m not sure what her issue is, but she obviously is a very bitter and unhappy person. She is holding onto that bitterness for some reason whatever that might be. As a woman, I must say that there are some of us out there who do not think or act like she does. The beauty of life is all the differences between the masculine and the feminine in however that manifests itself considering the original topic of Rajini Rao article. Without variety this life would be incredibly boring. You can not blame the male gender for those heinous crimes you can only blame the one who committed the crime not an entire gender. What a sad and pathetic life she must have, to feel that she has to attack someone in order to give herself some sort of meaning. 

  68. Kalua J.K says:

    Wow! I don’t know why but I feel really sad for this person to be so full of confusion, bitterness and really hate for life and really when she says all these horrible things to other people what she is really saying is how much she hates herself and that she is full of envy. 

  69. Tom Lee says:

    It’s a heck of a confused world out there we have to deal with nowadays.

  70. daniel wyatt says:

    it really is amazing .. the complexities of physiology

  71. you mean if a woman runs a lot or lifts weights a lot, there is a probability of her turning into a male?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s