The Australian team practices before competing in the Open Team Free Final at the World Aquatics Artistic Swimming World Cup Super Final Budapest 2024 this July.David Balogh—Getty Images

In late 2022, the International Olympic Committee (IOC) announced that at this summer’s Paris Olympic Games, men would be allowed to compete in artistic swimming (previously known as synchronized swimming)
events for the first time. The announcement signaled a major reversal for what has long been perceived as a “women’s sport”—codified as such by the IOC when it accepted synchronized swimming as an Olympic event in 1984 for female competitors only. The sport remained closed to men for the next nine Olympiads.

For American Bill May—who became a national champion in the 1990s—the announcement has been nearly a lifetime in the making. May told NBC Sports that when he got the phone call alerting him of the news, “It’s like my heart exploded.” At the age of 44, May came out of retirement and began training on the U.S. Senior National Artistic Swimming Team with the goal of finally realizing his Olympic dream.

Despite the elation expressed by male artistic swimmers around the world at the decision, neither May nor any other male competitor from the ten countries that qualified for the team event will be competing in Paris. It turns out that reversing the impact of decades of exclusion, even for a sport that was originally co-ed, is no simple matter. Synchronized swimming has long been associated with femininity, which spurred its early growth and even helped it become an Olympic sport, but over the years that association has also reinforced the exclusion of male athletes.

The term “synchronized swimming” dates to the 1934 Chicago World’s Fair, where physical educator Katharine Curtis debuted a new style of group swimming set to music. Curtis soon founded co-ed synchronized swimming clubs at two different teaching colleges in Chicago, and when the two groups held a synchro swim-off in 1939, it marked the sport’s first competition.

Soon after, synchronized swimming was accepted into the Amateur Athletic Union (AAU), the governing body for competitive sports at the time. It did so, however, as separate events for women and men. That decision would prove to be the death knell for men in the sport, as there was little interest in male-only synchro events and within a few years their competitions stopped altogether.

The world of show business reinforced the view of synchronized swimming as an activity for women—from filmmaker Busby Berkeley’s water ballets featuring female swimmers in shifting kaleidoscopic patterns to theater impresario Billy Rose’s world’s fair “Aquacades,” whose swimmers were often likened to wet Rockettes. The star of Rose’s California Aquacade, Esther Williams, was recruited by MGM to swim in their splashy Technicolor “aquamusicals,” which catapulted the national swimming champion to stardom and further glamorized the water.

By the mid-1950s, there were—according to Sports Illustrated—roughly 25,000 practitioners of synchronized swimming in the U.S., and the sport had been accepted by FINA, the international swimming federation, as a new aquatic discipline for women. With this international growth, synchro swimmers set their sights on the Olympics, but their lobbying to the all-male IOC was repeatedly ignored. IOC President Avery Brundage, who called synchronized swimming “aquatic vaudeville,” hadn’t wanted women in the Olympics in the first place—even suggesting as late as 1953 that eliminating all women’s events could be a way for the IOC to cut costs.

Once the Title IX era began in the early 1970s, however, being a women’s sport was suddenly no longer a hindrance. With the U.S. mandate to eliminate gender-based discrimination in schools signed into law, a widespread movement toward greater women’s inclusion in sports spread internationally, and synchro was accepted for the 1984 Olympics, along with rhythmic gymnastics, another women-only sport. The New York Times declared them the new Olympic “glamour events.” The majority of articles about synchronized swimming focused on its aesthetics like hair gel and bedazzled costumes worn by the athletes, further cementing the idea that the world of competitive synchro was a feminine, performative domain.

Although men remained excluded from international competitions, within the United States, they had been welcomed back in 1979. Leaders in the sport broke away from the AAU, forming U.S. Synchronized Swimming, and quickly repealed the longstanding separation of men and women.

That reversal enabled Bill May, who was born that same year, to develop his talent, join the elite Santa Clara Aquamaids, and then earn a spot on the national team. Yet when May remained ineligible due to his sex to try out for the 2000 Olympic squad, he became a cause célèbre for men’s Olympic inclusion.

FINA warned that pushing for men’s acceptance, however, could hurt the sport’s standing. “When we got to the Olympics,” said Chris Carver, May’s coach, “I think people were very much afraid that our unique status as a women’s sport had helped us get there.” Men remained locked out of the top international competitions until 2015, when FINA added mixed duets at the World Aquatic Championships in Kazan, Russia.

Not everyone liked the change, including Russian sports minister Vitaly Mutko who said that synchro should remain “a purely feminine sport.” Pop culture had long portrayed synchronized swimming as a hyper-feminine activity and depicted male practitioners only in spoof fashion, such as Austin Powers in his pink flowered swim cap (1999) or Martin Short and Harry Shearer’s now-classic Saturday Night Live “mockumentary” (1984).

To counter these stereotypes, mixed-duet choreography often plays up traditional gender dynamics, rather than the “matchy-matchy” style of female duets. “In a mixed duet the man should personify strength, power,” said Russian artistic swimmer Aleksandr Malstev, who won the gold medal for his free mixed duet in Kazan. “The woman, on the contrary, beauty and grace.”

After 2015, mixed duets seemed like the natural entry point for men into Olympic artistic swimming. So it came as a surprise when the IOC announced that it would accept men at the 2024 Summer Games not as part of mixed pairs, but rather by allowing up to two men to compete in each country’s eight-member team.

The decision creates challenges. “A guy fires his muscles differently than a woman, their strength is different, their buoyancy is different, and, a lot of times, flexibility is different,” explained May in a phone interview. “Trying to make all of that complement each other is very difficult.” But if you put in the effort to make athletes of differing body types meld, he said, “then you’re going to get something really remarkable.”

May was among the swimmers who competed at the Olympic qualifiers earlier this year and earned the U.S. a spot in Paris, marking an historic comeback for the country, which had not qualified since 2008. But when the 12-member national team was narrowed down to an Olympic squad of eight, May did not make the cut.

The continued absence of men at the Olympics is, to May and so many others, a lost opportunity for both the sport and the development of male athletes. In order to “catch up” he says, men need the experience of melding seamlessly with seven other athletes, which is entirely different from swimming duets.

Moreover, it is important for young boys and others who don’t identify with the traditionally feminine aesthetic to see athletes like them competing on the global stage. To May, who now coaches his former team—recently rebranded from the Aquamaids to Santa Clara Artistic Swimming to be more gender inclusive—the only way for the sport to grow is through the inclusion of all athletes. “It does take a lot of nurturing,” he says, “but the outcome is far beyond our understanding of how the sport will be this year, next year… in future years to come.”

Vicki Valosik is a masters synchro swimmer, an editorial director at Georgetown University, and the author of the new book Swimming Pretty: The Untold Story of Women in Water, which traces the origins and development of artistic swimming.

Made by History takes readers beyond the headlines with articles written and edited by professional historians. Learn more about Made by History at TIME here. Opinions expressed do not necessarily reflect the views of TIME editors.