Billionaire Elon Musk, known for his controversial stances, has once again ignited the debate on gender and sports by publicly calling for a boycott of an international swimming tournament that allowed biological men to compete in women’s categories.

In a series of posts on X on Thursday night, Musk, who has over 200 million followers on the platform, stated: “No biological man should compete in women’s categories. This is unfair and kills the spirit of sports! Boycott this tournament now!”

The statement, tagged with #BoycottSwimTour, quickly reached 18 million views, sparking a wave of polarized reactions and reigniting a global discussion on fairness in sports.

The tournament in question, the Global Swim Championships 2025, held in Sydney, Australia, adopted an inclusive policy allowing transgender athletes to compete in women’s categories, provided they meet the testosterone level criteria set by the International Swimming Federation (FINA).

Among the competitors was American transgender swimmer Lia Thomas, who had already been at the center of controversy in 2022 after winning women’s competitions. Thomas returned to the headlines after securing a gold medal in the 200-meter freestyle, narrowly defeating Australian swimmer Emma Carter by less than a second.

Thomas’s victory, widely celebrated by LGBTQ+ rights activists, became the catalyst for Musk’s outrage and that of other critics who argue that biological men have innate physical advantages, regardless of hormone treatments.

Musk, who had previously voiced his opposition to the participation of biological men in women’s sports—such as in 2024 when he criticized Algerian boxer Imane Khelif during the Paris Olympics—intensified his rhetoric.

“It’s a disgrace to see women’s sports being destroyed by ‘woke’ policies that ignore basic science. Women deserve to compete on equal terms!” Musk wrote, echoing sentiments shared by figures like former American swimmer Riley Gaines, who also called for a boycott of the tournament.

Gaines, who competed against Thomas in 2022 and has since become a prominent voice against the inclusion of trans athletes in women’s sports, posted on X: “Elon is right. This is not inclusion, it’s injustice. #BoycottSwimTour.”

The controversy exploded on social media, with #BoycottSwimTour and #SwimFairness trending globally.

On one side, supporters of Musk and Gaines argue that biology gives biological men advantages such as greater muscle density and lung capacity, even after gender transition. “Lia Thomas may have regulated testosterone levels, but she still has a male body that gives her an unfair advantage!” tweeted @SportsTruth2025.

On the other side, advocates for inclusion, including organizations like the Human Rights Campaign, condemned Musk’s statements as transphobic. “This is pure prejudice disguised as concern for sports. Trans athletes deserve to compete like anyone else,” posted @TransRightsNow.

FINA, which revised its policies in 2022 to require that trans athletes complete their transition before the age of 12 or maintain testosterone levels below 2.5 nmol/L, defended the tournament. “Our rules are based on science and ensure fairness. Lia Thomas has met all the criteria,” a federation spokesperson told The Guardian.

However, critics argue that such policies do not address structural advantages, such as Thomas’s average height of 5’10” compared to the 5’5” average of female competitors, or her larger wingspan—factors that directly influence swimming performance.

The controversy gained even more momentum as other public figures joined the debate. Former U.S. President Donald Trump, an ally of Musk, posted on X: “I agree with Elon—biological men in women’s sports is a fraud. Let’s protect our female athletes!”

Meanwhile, Vice President Kamala Harris, who had previously congratulated Thomas on her achievements in 2022, called for moderation, telling CNN: “We must seek a balance between inclusion and fairness, but attacks like these only fuel hate.”

Swimmer Emma Carter, who lost to Thomas, avoided direct criticism but told the Sydney Morning Herald: “I gave it my all, but it’s hard to compete when the rules feel so unequal.”

Musk’s call for a boycott is already impacting the tournament. Sponsors like Speedo and Omega are facing pressure to take a stance, with some users on X threatening to boycott their brands.

According to preliminary Nielsen data, the event’s live broadcast viewership has dropped by 15% compared to expectations.

Anti-trans activists are planning protests at the venue, while pro-LGBTQ+ groups are organizing a vigil in support of Thomas, increasing the risk of confrontations.

Musk, who has a history of conservative stances on gender issues—such as his criticism of the “woke mind virus” in relation to his transgender daughter Vivian Jenna Wilson’s transition in 2022—seems determined to keep up the pressure.

His political involvement, including his support for Trump and his role as an efficiency advisor in the government, adds a layer of influence to his statements but also attracts accusations of hypocrisy.

Critics on X point out that Musk, who has faced lawsuits over questionable labor practices at his companies—such as Tesla, where women have reported systemic sexism—lacks the moral authority to speak about fairness.

As the controversy intensifies, the sports world faces a dilemma: how to balance inclusion and competitive fairness in a landscape where science, politics, and emotions collide.

The Global Swim Championships 2025 could be a turning point, forcing federations to reassess their policies or risk further boycotts.

Meanwhile, Musk’s voice continues to resonate, further polarizing an already heated debate.