World-class South African athlete Caster Semenya, age 18, won the 800 meters in the International Association of Athletics Federations World Championships on August 19. But her victory was all the more remarkable in that she was forced to run amid a controversy that reveals the twisted way international track and field views gender.

The sports world has been buzzing for some time over the rumor that Semenya may be a man, or more specifically, not “entirely female.” According to the newspaper The Age, her “physique and powerful style have sparked speculation in recent months that she may not be entirely female.” From all accounts an arduous process of “gender testing” on Semenya has already begun. The idea that an 18-year-old who has just experienced the greatest athletic victory of her life is being subjecting to this very public humiliation is shameful to say the least.

Her own coach Michael Seme contributed to the disgrace when he said, “We understand that people will ask questions because she looks like a man. It’s a natural reaction and it’s only human to be curious. People probably have the right to ask such questions if they are in doubt. But I can give you the telephone numbers of her roommates in Berlin. They have already seen her naked in the showers and she has nothing to hide.”

The people with something to hide are the powers that be in track and field, as well as in international sport. As long as there have been womens’ sports, the characterization of the best female athletes as “looking like men” or “mannish” has consistently been used to degrade them. When Martina Navratilova dominated women’s tennis and proudly exposed her chiseled biceps years before Hollywood gave its imprimatur to gals with “guns,” players complained that she “must have a chromosome loose somewhere.”

This minefield of sexism and homophobia has long pushed female athletes into magazines like Maxim to prove their “hotness”–and implicitly their heterosexuality. Track and field in particular has always had this preoccupation with gender, particularly when it crosses paths with racism. Fifty years ago, Olympic official Norman Cox proposed that in the case of black women, “the International Olympic Committee should create a special category of competition for them–the unfairly advantaged ‘hermaphrodites.'”

For years, women athletes had to parade naked in front of Olympic officials. This has now given way to more “sophisticated” “gender testing” to determine if athletes like Semenya have what officials still perceive as the ultimate advantage–being a man. Let’s leave aside that being male is not the be-all, end-all of athletic success. A country’s wealth, coaching facilities, nutrition and opportunity determine the creation of a world-class athlete far more than a Y chromosome or a penis ever could.

What these officials still don’t understand, or will not confront, is that gender–that is, how we comport and conceive of ourselves–is a remarkably fluid social construction. Even our physical sex is far more ambiguous and fluid than is often imagined or taught. Medical science has long acknowledged the existence of millions of people whose bodies combine anatomical features that are conventionally associated with either men or women and/or have chromosomal variations from the XX or XY of women or men. Many of these “intersex” individuals, estimated at one birth in every 1,666 in the United States alone, are legally operated on by surgeons who force traditional norms of genitalia on newborn infants. In what some doctors consider a psychosocial emergency, thousands of healthy babies are effectively subject to clitorectomies if a clitoris is “too large” or castrations if a penis is “too small” (evidently penises are never considered “too big”).

The physical reality of intersex people calls into question the fixed notions we are taught to accept about men and women in general, and men and women athletes in sex-segregated sports like track and field in particular. The heretical bodies of intersex people challenge the traditional understanding of gender as a strict male/female phenomenon. While we are never encouraged to conceive of bodies this way, male and female bodies are more similar than they are distinguishable from each other. When training and nutrition are equal, it is increasingly difficult to tell the difference between some of the best-trained male and female Olympic swimmers wearing state-of-the-art one-piece speed suits. Title IX, the 1972 law imposing equal funding for girls’ and boys’ sports in schools, has radically altered not only women’s fitness and emotional well-being but their bodies as well. Obviously, there are some physical differences between men and women, but it is largely our culture and not biology that gives them their meaning.

In 1986 Spanish hurdler Maria José Martínez-Patiño was stripped of her first-place winnings when discovered to have an XY chromosome, instead of the female’s XX, which shattered her athletic career and upended her personal life. “I lost friends, my fiancé, hope and energy,” said Martínez-Patiño in a 2005 editorial in the journal The Lancet.

Whatever track and field tells us Caster Semenya’s gender is–and as of this writing there is zero evidence she is intersex–it’s time we all break free from the notion that you are either “one or the other.” It’s antiquated, stigmatizing and says far more about those doing the testing than about the athletes tested. The only thing suspicious is the gender and sex bias in professional sports. We should continue to debate the pros and cons of gender segregation in sport. But right here, right now, we must end sex testing and acknowledge the fluidity of gender and sex in sports and beyond.