Lia Catherine Thomas was born in May 1999 and assigned male at birth. She is an American swimmer and became the first openly transgender athlete to win an NCAA Division I national championship.

Thomas began swimming at the age of five.

Thomas competed for Westlake High School and finished sixth in the state high school swimming championships for boys' events.

Thomas began attending the University of Pennsylvania.

While on the men's team, Thomas recorded a time of eight minutes and 57.55 seconds in the 1,000-yard freestyle, ranking as the sixth-fastest national men's time. She also achieved top 100 national rankings in the 500-yard and 1,650-yard freestyle events.

Thomas came out as transgender to her family after her freshman year at college.

Thomas finished second in the men's 500, 1,000, and 1,650-yard freestyle at the Ivy League championships.

Thomas came out as a trans woman to her coaches, friends, and the swim teams at the University of Pennsylvania during her junior year.

Thomas was required to swim for the men's team while undergoing hormone therapy.

Thomas began transitioning using hormone replacement therapy.

Conservative media, including Fox News, began widely covering Thomas.

Thomas met the NCAA hormone therapy requirements to swim on the women's team.

Thomas swam on the women's team after taking a year off school.

Anonymous parents of University of Pennsylvania swim team members wrote to the NCAA, seeking for Thomas to be declared ineligible to compete.

USA Swimming official Cynthia Millen resigned after 30 years in protest against Thomas's eligibility to compete.

Thomas finished in 6th place in the 100m freestyle race at a meet against Yale, losing to four cisgender women and a transgender man.

The University of Pennsylvania, organizations affiliated with the law school, and the Ivy League issued statements supporting Thomas.

Sixteen anonymous members of the University of Pennsylvania women's swimming team sent a letter asking officials not to take legal action against a proposed NCAA transgender athlete policy.

Thomas became the first openly transgender athlete to win an NCAA Division I national championship in any sport, winning the women's 500-yard freestyle.

Sports Illustrated reported that Thomas applied for law school and planned to swim at the 2024 Summer Olympics trials.

Florida governor Ron DeSantis issued a proclamation declaring Emma Weyant the "rightful winner" of the 2022 NCAA Division I Women's 500-yard Freestyle.

Thomas defended herself from criticism and stated her intention to keep swimming and compete at the Olympic trials.

The International Swimming Federation (FINA) voted to bar transgender athletes from competing in professional women's swimming under certain conditions.

Thomas opened a legal challenge to the World Aquatics gender inclusion policy, arguing that it is discriminatory.

The Court of Arbitration for Sport ruled that Thomas did not have standing to challenge the World Aquatics policy, keeping her ineligible to compete.

The Trump administration stripped away $175 million dollars of federal funding from UPenn over their allowing Thomas to swim as a woman, accounting for 17.5% of the university's total federal funding.