The Sports Gene: Inside the Science of Extraordinary Athletic Performance (7 page)

In several popular books that give short shrift to the importance of genes, Tiger Woods is put forth as the apotheosis of the 10,000-hours model. His father facilitated colossal amounts of early childhood practice. But, by Woods’s account, that was in response to his own desire to play. “To this day,” Woods said in 2000, “my dad has never asked me to go play golf. I ask him. It’s the child’s desire to play that matters, not the parent’s desire to have the child play.” With Woods, one oft-omitted fact about his childhood is that, at six months old, when most infants are just beginning their struggle to stand, he could balance on his father Earl’s palm as Earl walked around the house. Not to say that this necessarily destined Woods for superhuman coordination or strength as an adult, but at the very least it would seem to have given him an opportunity to start practicing earlier than other children so that he was hitting balls at eleven months. Perhaps another case of physical hardware facilitating the download of sport-specific software.

The “practice only” narrative to explain Tiger Woods has an obvious attraction: it appeals to our hope that anything is possible with the right environment, and that children are lumps of clay with infinite athletic malleability. In short, it has the strongest possible self-help angle and it preserves more free will than any alternative explanation. But narratives that shun the contributions of innate talent can have negative side effects in exercise science.

Sports scientists who do genetic work occasionally told me that their research has a public relations problem stemming from the idea that genes are rigidly deterministic, and that they negate free will or the ability to improve one’s athletic station. Some genes—like the ones that give you two eyeballs or the one for the degenerative brain disease Huntington’s—are rather deterministic. If you have the genetic defect
for Huntington’s, you will get the disease. Many other genes, however, are not biological destiny, but simply tilt one’s physical predispositions. Unfortunately, that moderate message is often entirely lost in a mainstream press that heralds each study of a new gene as if it completely supplants some aspect of human agency.

Jason Gulbin, the physiologist who worked on Australia’s Olympic skeleton experiment, says that the word “genetics” has become so taboo in his talent-identification field that “we actively changed our language here around genetic work that we’re doing from ‘genetics’ to ‘molecular biology and protein synthesis.’ It was, literally, ‘Don’t mention the g-word.’ Any research proposals we put in, we don’t mention the genetics if we can help it. It’s: ‘Oh, well, if you’re doing molecular biology and protein synthesis, well, that’s all right.’” Never mind that it’s the same thing.

Several sports psychologists I interviewed told me that they publicly support a view that marginalizes genes because they believe it sends a positive social message. “But maybe it’s dangerous too,” one eminent sports psychologist told me, “to say that you’re stuck where you are because you’re not working hard enough.” Either way, the social message has no bearing on the scientific truth.

Janet Starkes, whose work, along with Ericsson’s, helped usher in the era of “software not hardware,” always believed that genetic differences played a part in sport skill, but in the past she was reticent to say so publicly. “Thirty-five years ago, people very easily accepted that there are underlying innate abilities,” Starkes says. “As the [learned] perceptual cognitive approach became more acceptable, it allowed me to be more centrist. It’s really been very much of a pendulum swing. . . . Darts is the most closed motor skill you can get, but practice still cannot explain all the variance. And to hit [a baseball] you’ve got to have a modicum of visual acuity, and it’s better if it’s better, and you also definitely need the software to go with it.”

Starkes has contributed as much to the study of skill practice as any sports scientist alive. Her work forms a full vertebra in the backbone of
the strict 10,000-hours view—that only practice determines success in sports. And yet, even when she was afraid to say it, Starkes knew that without genes, the picture of sports expertise is woefully incomplete.

After all, Starkes adds, if only accumulated hours of practice matter, then why do we separate men and women in athletic competition?

It’s a good question.

Why Men Have Nipples

C
ertainly, María José Martínez-Patiño never had reason to doubt her womanhood. Her face was slender and regal, its eggshell skin stretched delicately over high cheekbones. She grew up a very normal girl in northern Spain, save for being better than her peers at running and jumping.

In 1985, Martínez-Patiño, an internationally accomplished twenty-four-year-old sprint hurdler, arrived at the World University Games in Kobe, Japan, only to realize that she had forgotten the doctor’s certificate that declared that she was a woman and could compete against women. So, in Kobe, she had to take the customary precompetition cheek swab to establish her biological sex.

Sex testing had been in place since the 1960s, when the International Association of Athletics Federations had seen enough brawny Eastern Bloc women—many of whom were on elaborate doping programs—that it instituted regulations to ensure that male athletes were not masquerading as females. (No such case has ever been confirmed.) Early on, testing was a crude affair. Women were made to drop their pants in front of a doctor. By the 1968 Olympics in Mexico City, that degrading procedure was replaced by tidily objective technology: swabs of cheek tissue that were tested for chromosomes. Women have XX sex chromosomes and men have XY.

Except, that is, when they don’t.

Late on that August day in ’85, the Spanish team doctor came to Martínez-Patiño with news. There was a problem with her test, and she would be unable to compete. Martínez-Patiño wondered whether she might have AIDS, or perhaps leukemia, which had taken the life of her brother. But the doctor would say no more.

She lived with crushing anxiety for two months. She visited doctors, but always alone, to spare her parents, who were still mourning her brother. Then the letter came. It wasn’t AIDS, or leukemia, but the diagnosis would change her life. The letter said that each of the fifty cells analyzed from her cheek contained XY chromosomes.
Surprise! You’re a man
. Team officials urged Martínez-Patiño to fake an injury and slink softly into retirement.

Not only did she refuse to retire, but three months later Martínez-Patiño won the Spanish national title in the 60-meter hurdles. The glory of her victory ensured her own public ridicule. The result of Martínez-Patiño’s sex test was leaked to the press. The spiraling descent was swift, and cruelly thorough.

Everything that could be taken was taken. Spanish officials stripped Martínez-Patiño of her national title. They evicted her from the national athletes’ living quarters. They revoked her scholarship. They expunged records of her athletic performances, as if she had never existed. Her friends sorted into those who stayed and those who fled. Her fiancé was among the latter.

Martínez-Patiño was ashamed. She lost her energy. But her resilience held fast. She maintained in the press that she was sure of her womanhood. She vowed to fight back, and help came from afar.

A Finnish geneticist named Albert de la Chapelle saw a news article about Martínez-Patiño’s struggle and spoke out. De la Chapelle knew quite well that chromosomes do not necessarily make the man or woman. He had pioneered the study of individuals with XX chromosomes who develop as males. “De la Chapelle syndrome” can occur when the parents’ X and Y chromosomes don’t line up perfectly as they
exchange information, and genes from the tip of the Y chromosome break off and end up on an X.

Martínez-Patiño paid thousands of her own dollars to be examined by doctors. They told her that she had testes, hidden from sight inside her labia, and that she had neither a uterus nor ovaries. But the doctors also discovered that, while her testes were producing male levels of testosterone, Martínez-Patiño had androgen insensitivity. That is, her body was deaf to the call of testosterone, and so she developed entirely as a woman. Most women can take advantage of the athletic benefits of the small amount of testosterone their bodies produce, but Martínez-Patiño could use none at all.

Nearly three years after her sex test became public, the Olympic Medical Commission met at the 1988 Games in Seoul, South Korea, and decreed that Martínez-Patiño should be reinstated. By that time, though, her career had been derailed, and she missed qualifying for the 1992 Olympics by one tenth of a second.

In 1990, spurred by Martínez-Patiño’s ordeal, the IAAF convened an international group of scientists to decide, once and for all, how to tell a man from a woman for the purposes of competition. The experts’ answer:
Don’t ask us!
The group instead recommended dropping sex-verification testing altogether. By 1999, the International Olympic Committee was down to testing women only in cases where suspicion arose, and even then they had no clear standard for what constituted an eligible woman.

The trouble is that human biology simply does not break down into male and female as politely as sports governing bodies wish it would. And no technological advances of the last two decades have made the slightest difference, nor will any in the future. “I don’t see how one could come up with anything different than we did twenty years ago,” says Myron Genel, professor emeritus of pediatrics at Yale and a member of the group that advised the IAAF to drop the testing.

Doctors ultimately decided that Martínez-Patiño had been treated unfairly. She was, they determined, a woman for competitive purposes.
A woman with both a vagina and internal testes, breasts but no ovaries or uterus, and male doses of testosterone that circulated inertly through her body.

Neither body parts nor the chromosomes within them unequivocally differentiate male from female athletes. Is there, then, a genetic reason to separate men and women at all?

•

“Will Women Soon Outrun Men?” The title of the paper by a pair of UCLA physiologists seemed preposterous to me when I first saw it in 2002, as a senior in college. I had trained as an 800-meter runner for just five seasons and had already run faster than the women’s world record. And I wasn’t even the fastest guy on my own relay team.

But the article was in the journal
Nature
, one of the most prestigious scientific publications on the planet, so there had to be something to it. The public thought so. Of one thousand Americans surveyed by
U.S. News & World Report
prior to the 1996 Atlanta Olympics, two thirds felt that “the day is coming when top female athletes will beat top males.”

The authors of the
Nature
paper graphed men’s and women’s world records through history for every event from the 200-meters to the marathon and saw that the improvement in women’s records was far steeper than the improvement in men’s. By extrapolating the curves into the future, the authors determined that women would beat men in all running events in the first half of the twenty-first century. “It is the
rates
of improvement that are so strikingly different,” the authors wrote. “The gap is progressively closing.”

In 2004, with the Athens Olympics as a news hook,
Nature
featured another such article, this one titled “Momentous Sprint at the 2156 Olympics?”—a reference to the projected date when women would outstrip men in the 100-meter dash.

In 2005, a paper by a trio of exercise scientists in the
British Journal of Sports Medicine
did away with the question mark and simply proclaimed in its title, “Women Will Do It in the Long Run.”

Could it be that male dominance of world records was all along an artifact of discrimination that kept women from competing?

In the first half of the twentieth century, cultural norms and pseudoscience severely limited women’s opportunities for athletic participation. At the 1928 Olympics in Amsterdam, the media account (which was fabricated) of exhausted female competitors lying on the ground after the 800-meter race was so distasteful to some doctors and sportswriters that the event was deemed hazardous to female health. “This distance makes too great a call on feminine strength,” read a
New York Times
article.
*
After those Olympics, all women’s events longer than 200 meters were summarily banned from the Games for the next thirty-two years. It was not until the 2008 Olympics that women finally had all the same track events as men. But as women competed in greater numbers, the
Nature
papers suggested, it looked as if they might eventually be athletically equivalent to or even better than men.

When I visited Joe Baker, a sports psychologist at York University, we discussed male/female differences in athletic performances, particularly the difference in throwing. Of all the sex differences that have ever been documented in scientific experiments, throwing is consistently one of the largest. The difference in average throwing velocity between men and women, in statistical terms, is three standard deviations. That’s about twice as large as the male/female disparity in height. That means that if you pulled a thousand men off the street, 997 of them would be able to throw a ball harder than the average woman.

Baker noted, though, that the situation could reflect a lack of training in women. His wife grew up playing baseball and can easily out-throw him. “She has a laser beam,” he joked. So is the difference biological?

The DNA differences between men and women are extremely small, limited to the single chromosome that is either X in women or Y in men. A sister and brother draw their genes from the exact same sources—though mixing of the mother’s and father’s DNA, known as recombination, ensures that siblings are never close to being clones.

Much of sexual differentiation comes down to a single gene on the Y chromosome: the SRY gene, or “sex determining region Y” gene. Insofar as there is an “athleticism gene,” the SRY gene is it. Human biology is set up such that the same two parents can produce both masculine sons and feminine daughters even though they’re passing on the same genes. The SRY gene is a DNA skeleton key that selectively activates genes that make the man.

We all begin life as females. Every human embryo is female for the first six weeks of existence. Because mammal fetuses are exposed to a hefty dose of female hormones from the mother, it is more economical to have the default sex be female. In males, in week six, the SRY gene cues the formation of testicles and, inside them, the Leydig cells that synthesize testosterone. Within a month, testosterone is gushing and triggering specific genes to turn on and others off, and it doesn’t take long for the long throwing disparity to emerge.

Boys, while still in the womb, start to develop the longer forearm that will make for a more forceful whip when throwing. And while the pronounced differences in throwing prowess are less between boys and girls than between men and women, they are already apparent in two-year-old children.

In an effort to determine how much of the throwing gap among children is cultural, a team of scientists from the University of North Texas and the University of Western Australia collaborated to test both American and Aboriginal Australian children for throwing skill. The Aboriginal Australians had not developed agriculture, instead remaining hunter-gatherers. The Aboriginal Australian girls, like the boys, were taught to throw projectiles for both combat and hunting. Indeed, the study found that throwing differences were much less pronounced
between Australian Aboriginal boys and girls than between American boys and girls. But the boys still threw far harder than the girls, despite the fact that the girls were taller and heavier by virtue of their earlier maturation.

Not only are boys generally superior at throwing, but they also tend to be much more skilled at visually tracking and intercepting flying objects; 87 percent of boys outperform the average girl in tests of targeting skills. And the difference appears to be at least partly a result of exposure to testosterone in the womb. Girls who are exposed to high levels of testosterone in the womb because of a genetic condition called congenital adrenal hyperplasia, in which the fetal adrenal glands overproduce male hormones, perform like boys, not girls, on these tasks.

Highly trained women easily out-throw untrained men, but highly trained men vastly out-throw highly trained women. Male Olympic throwers heave the javelin about 30 percent farther than female Olympians, even though the women’s javelin is lighter. And the Guinness World Record for the fastest baseball pitch by a woman is 65 mph, a speed routinely topped by decent high school boys. Some professional men can throw over 100 mph.

In running, from the 100-meters to the 10,000-meters, the rule of thumb places the elite performance gap at 11 percent. The top ten men in any distance—from a sprint to an ultramarathon—are about 11 percent faster than the top ten women.
*
At the professional level, that is a gulf. The women’s 100-meters world record would have been too slow by a quarter-second to qualify for entry into the men’s field at
the 2012 Olympics. In the 10,000-meters, the women’s world record performance would be lapped by a man who made the minimum Olympic qualifying standard.

Larger gaps occur in throwing and pure explosion events. In the long jump, women are 19 percent behind men. The smallest gap occurs in distance swimming races. In the 800-meter freestyle, top women are within 6 percent of top men.

The papers that predicted that women will overtake men implied that the progression of women’s performances from the 1950s to the 1980s was part of a stable trajectory that would continue, when in reality it was a momentary explosion followed by a plateau—a plateau that women, but not men, have reached. While women began leveling off by the 1980s in terms of top speed in events from the 100-meters to the mile, men continued to inch forward, albeit barely.

The numbers are unequivocal. Elite women are not catching elite men, nor maintaining their position. Men are ever so slowly pulling away. The biological gap is expanding.

But why does it exist in the first place?

•

Next to a Yellow Pages–thick dictionary on the windowsill of David C. Geary’s corner office sits a woman’s skull. She is overlooking the campus of the University of Missouri. “You can see the cranium is small,” Geary says. He has a gaunt face and turquoise-tinted irises. A curve of gray hair that rises from the front of his forehead looks a bit like a question mark, lending his face an appropriately inquisitive air. “Her brain was only about a third the size of ours. That’s why she’s by the dictionary, she has to practice a lot,” he jokes. Geary is referring to his scale model of the skull of Lucy, the famous
Australopithecus afarensis
ancestor of modern man whose 3.2-million-year-old bones were found in Ethiopia.