Just over two weeks ago, University of Pennsylvania collegiate swimmer Lia Thomas made history as the first openly transgender woman to win a NCAA Division I title. Her historic win in Atlanta on March 17 made headlines around the country.

U.S. Rep. Lauren Boebert (R-CO) chimed into the ensuing debate last week: She’s introduced a new proposal to honor the second-place finisher in the race, Emma Weyant, as the “rightful winner” of the women’s 500-yard freestyle event.

While speaking on Dan Caplis’ radio show Thursday, Boebert repeatedly misgendered Thomas and refused to acknowledge her gender identity, insinuating that she had wrongfully won the event by virtue of having been assigned male at birth.

“This was a women’s race, and a man improperly took first place,” she told Caplis. “I’m not a biologist, but I can define what a woman is.”

Doubling down on her incendiary rhetoric, Boebert went on to assert that Thomas had been “mediocre” as a male athlete and was competing as a woman simply to try to gain an advantage.

“He decided, ‘You know what? Rather than try harder to be better, I’m just going to pretend to be a woman and compete against them and get first place,’” Boebert said to Caplis. “It’s really disgusting.”

Boebert and others who oppose equity for transgender athletes claim that a person’s gender is biologically determined at birth – a notion that has long since been debunked by medical experts. Genetics may play a part in determining a person’s gender identity, but according to reporting by the New York Times, researchers generally agree that it “comes from the brain, not the body.”

The available evidence on gender identity suggests that it’s a complex interplay of biological, psychological, environmental, and social factors. People in the transgender community attest that being trans is not a “choice,” and many report feeling intense dysphoria – or a feeling of distress at being out of alignment with their true identities – before beginning their transitions.

But the debate over whether transgender athletes should be allowed to compete in sports has raged for years. In 2021 alone, 36 U.S. states introduced legislation to restrict transgender students from participating in school sports, and 10 states have passed such laws.

Chase Strangio and Gabriel Arkles of the ACLU wrote that these anti-transgender student athletic bills are rooted in baseless and damaging beliefs about transgender athletes, such as the idea that trans athlete participation harms cisgender women or that trans competitors’ physical traits give them an athletic advantage.

To date, there is no solid evidence that trans athletes possess physiological advantages or that they regularly outperform cisgender athletes in sports. According to the Philadelphia Inquirer, many expected Lia Thomas to dominate in the NCAA National Championship.

But she won only one out of the 18 scheduled events and didn’t set any new records.

Additionally, Strangio and Arkles wrote that transgender athletes face harassment, discrimination, violence, and other significant barriers that make it difficult for them to stay in school, let alone compete in sports. Excluding trans athletes from participating only further damages the transgender community and discourages an environment of caring and inclusion, the advocates wrote.

According to the ACLU advocates, transgender people need and deserve social affirmation and acknowledgment of their transitions. This acknowledgment includes being allowed to participate in sports teams that match their true gender identities.

As Thomas herself stated in an interview with Sports Illustrated, “The very simple answer is that I’m not a man. I’m a woman, so I belong on the women’s team. Trans people deserve that same respect every other athlete gets.”

Erica Sullivan, a U.S. Olympic swimmer, wrote an op-ed in Newsweek in support of Thomas and other transgender athletes, saying that protecting the rights of all women – trans women included – helps make women’s sports stronger.

“As a woman in sports, I can tell you that I know what the real threats to women’s sports are: sexual abuse and harassment, unequal pay and resources and a lack of women in leadership,” wrote Sullivan. “Transgender girls and women are nowhere on this list.”