"There's only one hard and fast rule in running: sometimes you have to run one hard and fast."

Wednesday, July 30, 2008

Gender, Genetics, Hormones and the Olympics

I'm hoping this leads to some uncomfortable water cooler conversations.

Dr. House Goes to the Olympics

In 1960, a woman qualified for the Canadian Olympic trials in the high jump, but didn't bother to go because she knew she couldn't compete at the games even if she won. She had a handicap that the Olympics treat as an advantage. The Olympics require women to prove they are actually women with both a physical exam and a chromosomal test, but the test is flawed. You may recall from a biology class that women have two X chromosomes and men have an X and a Y. Because each cell needs only one X, one of the two a woman carries gets deactivated and forms what's called a Barr body, which can be seen under a microscope. The Olympics standard is: Barr body means female. Unfortunately for this woman, she had only one X chromosome, a condition called Turner's syndrome; women with it generally are short with webbing of the skin of the neck - not exactly an advantage in high-jumping.

In the 1970's, Jarmila Kratachvilova was unbeatable in the 400 meter and 800 meter sprints, setting world records regularly (her 400m might still stand). Everyone who saw her, including me, thought she was a man. Even after she had a baby, people thought the whole pregnancy was faked. She did pass the gender test, so, being from behind the Iron Curtain, it was assumed that she was using steroids. She passed all doping tests of the time. Personally, I'd be willing to bet she had a condition known as 21-hydoxylase deficiency. Both men and women produce both testosterone and estrogen, just in different amounts. Androgens (male hormones) are produced first and some of these get converted into estrogens (female hormones). One of the enzymes that's involved in this process is called 21-hydroxylase; if it doesn't work well in a woman, the ratio of the hormones is off, leading to a masculine appearance, even though the total amount of androgens remains within limits considered normal for women.

About 10 years ago, a former Olympic female sprinter from Germany had a baby with a very peculiar birth defect. The child's muscle growth appeared to be unrestricted and, when a toddler, had the shape of a tiny powerlifter. The child had inherited a rare dominant gene from both parents (the father apparently was also an athlete, but little is known about him). The woman was able to develop powerful musculature with little effort, a distinct advantage in sprinting and this appears to be due to the muscles responding unusually to normal amounts of androgens. This appears to me to be an unfair advantage, but one that would be hard to govern against.

There are women who would not be able to compete at the Olympics because of a condition known as Androgen Insensitivity Syndrome. These women are completely normal women in every way that's important in sport, but genetically they're men. The condition is often noticed at birth, but sometimes it isn't until a teenager has failed to menstruate by age 15 or 16 that they find that there are testes where ovaries are expected. They produce testosterone at the level expected for men, but it isn't used and the small amount converted to estrogen is used.

It turns out that male and female aren't as cut-and-dried as most expect. About 1 in 100000 children are born with ambiguous genitals. Sometimes the parents decide to assign a gender at birth (almost invariably female), sometimes they wait until the child appears to have adopted a gender role, often they do nothing. One of the most common causes is adrenal hyperplasia, tumors (usually benign) that cause secretion of high amounts of androgens. Adrenal hyperplasia can have a large number of different symptoms with a wide variety in severity, but one result is women who cannot compete in the Olympics because the level of male hormones in their blood is above the range the Olympics decided is normal.

So...enjoy the Olympics! Everyone loves a freak show.
Note added: The standards in blogs are lower than in journalism, so I didn't check my facts. My argument for Kratachvilova works better if I'd said aromatase instead of 21-hydoxylase. 21-hydroxylase deficiency leads to adrenal hyperplasia, which I'd treated separately. The woman with Turner's might have been British and it might've been 1964. As pointed out in the comments, apparently the Olympics have abandoned the Barr body test for the Y-linked SRY gene.

The Sydney games had no gender test, but the Chinese, under Dr, Tian Qinjie, are using the criteria of external appearance of genitalia, hormone levels, chromosome analysis and SRY gene mapping. Five have failed thus far.


Tracizzle said...

Very interesting!

I have always been intrigued by this topic.

Nowadays, they don't use Barr bodies but rather a test for the actual SRY gene, which is felt to be the one gene that makes a man a man. As you may know, the default development for a fetus is into a girl but the SRY gene changes all that.

These are the issues I have always wondered about:

The Turner Girls (I don't think Turner's were banned from competition; there must have been another type of test).

The Klinefelter boys (XXY) have Barr bodies.

There are gender-indeterminate individuals out there who may not want to be tested.

There was a man who had a sex-change operation and was allowed to compete in some sport (was it the modern pentathlon?).

Lisa said...

Interesting the variations humans come in - and some think it is so clearcut!

keith said...

I just read about some two year old kid that has an enzyme disorder which gives him a very high metabolism, no body fat and extremely developed muscles.

his parents say they noticed he was odd when after he fell on his rump, he would catch himself by tensing his already freakishly evolved abdominal muscles.

he can do the iron cross (an extremely difficult gymnasics move), is as quick as a cat and powerfully fast.

i hope they discover how to give me that disorder before i turn 40.


SteveQ said...

I'd always assumed they'd switch to the SRY gene, but apparently the IOC isn't as slow to move as I thought. It still would discriminate against the androgen insensitive, genotypic male/phenoypic female. If they're using SRY, then Turner's wouldn't be a problem. Men with Klinefelters are never athletic.

I wasn't aware the Olympics allowed transgender athletes (I'll have to investigate - I doubt they do); the only case of which I'm aware was in professional tennis (Raskin). Fortunately, she wasn't particularly good.

Diane said...

Very interesting... You have a very good repertoire of knowledge.

Don said...


May I suggest a link related to the Beijing 2008 Olympic Games?

Our site:

URL: http://www.2008chinaolympics.com
Title: Beijing Olympics

Please let me know if you want a link back.
Many thanks for your reply.

Best Regards,


Anonymous said...

I have turner syndrome...am i a freak????

SteveQ said...

@Anonymous: No. Everyone has about seven mutations that can be seen physically. You just know what one of yours is. I've met a woman with Turner's who I would never have known had it, as she had a very mild version of it - I assume the same is true for you.

Claudia said...

It is not true at all that girls with Turner syndrome have mild to severe retardation.

SteveQ said...

Claudia, you're absolutely right. I was using very old information - and frankly, I never thought this would be read by anyone except my friends and certainly not after 5 years! I'll make the correction. Mea maxima culpa.