The case of South African sprinter Caster Semenya, whose sex came into question after she became the 800-metre world champion last month, has dismayed many academics and female athletes.
And it wasn't because "a secret man," as one British tabloid called the 18-year-old runner, may be in their midst.
They say the Semenya case shows that an old, ugly paradox is alive and well in women's sport: The same giant quadriceps and bulky shoulders that can clinch championships make athletes look "unfeminine" in the eyes of the world. And that can be a difficult reality for many women.
"There is still a real image that women athletes should be tennis players wearing short skirts and braided pony tails," says Kristin Gauthier, 28, a kayaker on Canada's national team. "It's a hard mould to fit into."
A study published by the International Journal of Eating Disorders in 2008 showed that athletic, university-aged women tend to have higher rates of behaviours linked to eating disorders compared with those who do not regularly exercise. Insecurity over certain body parts is also common - even among the sporting world's most powerful stars.
"I think they're too muscular. They're too thick," tennis champion Serena Williams said of her ripped arms in an Aug. 27 interview with People Magazine. "I know that toned arms are in now. Look at Michelle Obama. … I'm like, 'keep wearing strapless dresses!' But I don't like mine."
Experts say much of this stems from a media-driven portrayal of the "ideal" athletic body. Strong but lean athletes such as American swimmer Dara Torres garner exposure, whereas strong but bulky athletes are idolized less often, says Guylaine Demers, a University of Laval professor and president of Égale-Action, the Quebec association for the advancement of women in sport.
Sports officials also play a role in pushing a certain feminine ideal by mandating certain clothing - such as tiny bikinis in beach volleyball - in order to sell an activity, she adds.
"It's always like yes, we are good athletes but we are feminine," she said.Jessica Zelinka, a Calgarian who competed in the heptathlon in the Beijing Olympics, says she sees it play out on the track: The lean and muscular sprinters in their "butt huggers" garner plenty of attention from the cameras, while the bulky shot-put throwers in their baggy shorts perform virtually unnoticed.
"I'm lean and muscular ... but I still have issues with wearing butt huggers," she says. "They're so short they actually go up your butt. I don't want to go over the finish line with a huge wedgie and be thinking about that."
Whether bulky muscles are viewed as feminine by society, they are perfectly natural, says Bernard Corenblum, a Calgary endocrinologist.
Women and men make the same hormones, just in different quantities. "Male" hormones, which are called androgens and include testosterone, help build muscle, speed and strength, among other things. (In Ms. Semenya's case, Australian media reported testing found both male and female sex characteristics; these reports are unconfirmed.)
Woman who excel at sports that reward speed and strength - such as swimming or track and field - may be more likely to have naturally high levels of androgens, Dr. Corenblum explains. Those levels may also be why those women appear flat-chested, boyish looking, muscular, or don't menstruate regularly, he adds.
Does that make such a woman a man? Of course not, Dr. Corenblum says, although in some cases it means she has medical conditions. For example, polycystic ovary syndrome, a hormonal disorder that affects seven per cent of all women, can elevate androgen levels.
But those traits can make a woman self-conscious, and in some cases, that can lead to eating disorders, lack-lustre workouts, and even a premature exit from athletics, says Vikki Krane, a professor at Bowling Green State University in Ohio.
Dr. Krane has interviewed dozens of college-level athletes about how they negotiate femininity and muscularity. In a 2004 study published in the journal Sex Roles , she found that most of the college-level athletes she interviewed found it difficult to negotiate the social expectations around femininity with athleticism. They complained that men weren't interested in dating women with large, athletic bodies. They also engaged in many activities to enhance their femininity, such as braiding their hair and wearing ribbons.
"Initially they were shocked by the changes in their body," she said. "Not fitting into clothes, or the typical styles that other girls are wearing - this is a constant reminder that you're different."
She interviewed one 5-foot-11 hockey player who explained: "I weigh 187 pounds and I look at the number on the scale and say, holy crap, I'm fat."
But many of the athletes also reported that those same traits made them feel strong, capable, and powerful, she said.
Ms. Gauthier, who lives in Ottawa, is familiar with that duality. "When you're in your element and you're with your teammates it's fine. But then you go out and you want to dress up and nothing fits."
As she has matured, Ms. Gauthier said, she's learned to accept that her muscular back is what she needs to excel on the water. Similarly, Ms. Zelinka says any pressure she may feel to look a certain way won't keep her out of the gym.
"I would not take away from my performance to try and look more feminine," she said.
Sorting out the boys from the girls is no simple matter
Figuring out a person's sex can be wickedly complex. That's why the International Association of Athletics Federations' process for determining whether South African runner Caster Semenya is a woman called for a geneticist, an endocrinologist, a psychologist and others.
But even with all the tests in the world, the line that constitutes an "unfair advantage" is up for interpretation, says Alice Dreger, a bioethicist in the Feinberg School of Medicine at Northwestern University. Figuring out who's a female or male - or should compete as such - isn't as simple as looking for XX or XY chromosomes.
For example, women with complete Androgen Insensitivity Syndrome have XY chromosomes but are actually less able to process androgens - male hormones such as testosterone - than the average woman.
Should they have to compete with men, just because they have a Y chromosome?
On the other hand, naturally high androgen levels may give a woman an advantage in volleyball, as Dr. Dreger points out. But so does being six feet tall.
As scientists discover more ways that our genes and hormones affect who we are, wider testing of athletes for physical advantages may become an issue. Dr. Dreger argues that those clear policies need to come soon, so athletes such as Ms. Semenya can determine whether they're allowed to compete without the humiliation of a "failed" test after the medal has been won.
For more information on the history of gender testing and how it works, visit the Howard Hughes Medical Institute