In December 1935, the Czech track star Zdeněk Koubek announced that he was going to be living as a man. To sports fans, the news seemed hard to believe: Koubek had been assigned female at birth, and he had competed, and set a world record, in the women’s 800-meter dash.

But after years of expressing an affinity for masculinity, Koubek decided the category no longer fit him. He was going to undergo a series of operations in his home country of Czechoslovakia, he told the press. Afterward, he hoped to compete in men’s sports.

Koubek Becomes Global Star After Gender Transition

Koubek was not exactly famous prior to his gender transition. Though he had set a world record in the women’s 800-meter dash, only sports fans in Europe seemed to know his name. But after transitioning, Koubek became a global star.

He traveled to New York in August 1936 to perform on Broadway. He told the press that he was in talks with Paramount to develop a movie about his life. Later, he traveled to Paris, where he shared a stage with Josephine Baker. French newspapers paid as much as 1,000 francs for the chance to interview him. 

Publications from the New York Times to TIME chronicled his new life. Light sensationalism aside, many of the stories radiated empathy. Physical Culture, one of the most prominent sports magazines of the era, asked, “How is such a transformation possible? Can science alter the sex of a human being?” and concluded that transitioning gender was more common than most readers might think. Meanwhile, TIME wrote that, while “such cases of ‘sex change’ fascinate not only tabloid editors,” but “to sober medical men, it does not seem strange that Nature some times blurs sexual development in men & women.”

In the annals of sports history, Koubek was largely forgotten. But, according to the historian Lindsay Parks Pieper, Koubek's story “showcased the new technologies that rendered sex-reassignment surgery a possibility.” 

By deciding to live as a man, as he’d wanted to all his life, Koubek opened up a much bigger conversation about the permeability of categories of “male” and “female.”

A Belated Interest in Sports

Koubek was born in 1913 in the village of Paskov, in what would soon become Czechoslovakia. His family was working class: Koubek’s father worked as a coach driver, and Koubek himself got a job in a men’s clothing store when he was fourteen.

Growing up, Koubek had little desire to play sports. He just didn’t get the appeal. Watching athletes shake their legs and bounce up and down during pre-race warmups was bizarre. Who, he wrote in an essay published years later in the magazine the Prague Illustrated Reporter, would waste their time training for something so silly?

But when Koubek and his co-worker at the clothing store received an invite to a local track meet, Koubek grudgingly decided to go. Watching the meet set something off in him. The athletes moved with such mesmerizing grace, and he wanted to try it for himself. He began collecting sports magazines and cutting out photos of his favorite athletes.

'Astonishingly Quick Time' at 1934 Women's World Games

Because Koubek had been assigned female at birth, he enrolled in women’s track. At the time, few women’s sports were available at the Olympics, and so the highest level of competition for most track athletes was the Women’s World Games, an upstart rival to the Olympics that took place every four years.

After rising through the ranks of a track club in Brno, Koubek moved to Prague. There, he set his sights on the 1934 Women’s World Games, which were hosted in London. That August, at the games, Koubek lined up for his signature event: the women’s 800-meter dash.

It was almost a disaster. Koubek was slow to start, and was trailing in third on his first lap around the track. Seeing his window close, Koubek pushed himself faster, faster, until he was in a full-body sprint. Koubek sensed the audience around him going quiet, waiting to see how long he could keep up this speed. 

“In astonishingly quick time,” the papers reported later, Koubek edged out his competitors, and barreled across the tape in first place. In the process, he had set a new world record.

Gender Transition Largely Embraced by Public

After his victory at the Women’s World Games, Koubek decided to focus on himself. He couldn’t escape his own nagging discomfort with the gender he’d been assigned. His “soul” was “always more for being a man,” he told the press later. The following fall, he began seeing a doctor, who agreed to perform a series of operations and to certify Koubek as a man. Though Koubek felt at times like a “guinea pig” in the doctor’s office, that was the price of getting healthcare in 1935.

When Koubek went public with his decision to live as a man, the public largely embraced him. At that point, Koubek had retired from women’s sports, and he expressed his desire to instead compete against men. Even the head of the Women’s World Games, Alice Milliat, rejected a reporter’s question about whether to revoke Koubek’s gold medal. “If it is proved that [Koubek] has become a man, it is logical to consider that previously she was a woman,” Milliat said, noting that Koubek didn’t want to play in women’s sports anyway.

1936 Olympics Establishes New Policy on Gender

Koubek became a symbol of the vast possibility of gender. But to a small handful of officials at the Olympics, that possibility seemed to signal a problem.

Avery Brundage, an American sports official, began worrying about people he deemed “hermaphrodites” entering Olympics sports. In June 1936, he wrote to the head of the Olympics, “the question of the eligibility of various female (?) athletes has been raised because of apparent characteristics of the opposite sex,” and suggested, “it might be well to insist on a medical examination before participation in the Olympic games.” The panic seemed confused at best, punitive at worst—Koubek was not even trying to compete in women’s sports after transitioning gender.

A few months later, Brundage’s suggestion became policy. The International Amateur Athletic Federation—which is today known as World Athletics, and which governs track-and-field sports—passed a rule that August, at the Berlin Olympics, allowing for medical examinations of athletes whose sex was called into question.

As the Olympics ramped up their testing apparatus, however, Koubek himself faded into the background. As World War II approached, Koubek received a driver’s certificate that identified him as a man, and he married a woman named Uršulou Škrobačovou. He landed a job at the car company Škoda. In 1944, after 10 years away, Koubek quietly returned to sports. He enrolled in a newly formed men’s rugby league, RC Říčany, which practiced in the suburbs of Prague.

He never made it to the Olympics—he was now over 30—but he had found a way to play sports on his terms. 

HISTORY Vault: The First Olympics

Travel back to 776 B.C. to the world's first sports complex, Olympia--where every four years, Greek city-states set aside their differences and laid down arms to compete in peaceful games established to honor Zeus.