University of Pennsylvania swimmer Lia Thomas has attracted national attention for breaking records and renewed a debate about whether transgender athletes have an unfair advantage in women's sports competitions.

Thomas, a biological male who identifies as a woman, won a recent 200-yard freestyle race by coming within two seconds of the NCAA record set by Missy Franklin, who later became a gold medal-winning Olympic athlete, though Thomas still lags behind some top female swimmers in the United States.


Joanna Harper, a visiting fellow for transgender athletic performance at Loughborough University in England, who conducted several studies about whether transgender athletes have advantages in sports competitions, says Thomas continues to face stiff competition from other swimmers.

"She's probably going to qualify for the NCAA championship," she told the Washington Examiner. "She's got an outside shot at a medal, but winning seems extremely unlikely."

Most of the records Thomas has broken so far were from the University of Pennsylvania and in the Ivy League. But the Ivy League has historically not been at the top of the NCAA for female swimming.

"The Ivy League is not a fast league for swimming, so that’s why it’s particularly ridiculous that we could potentially have an NCAA champion. That’s unheard of coming from the Ivy League," an anonymous teammate of Thomas told Outkick.

In three races Thomas gained attention for (200-yard free, 500-yard free, and 1,650-yard free), the swimmer is behind the NCAA records set by Franklin and Katie Ledecky, both of whom went on to compete in the Olympics.

It is difficult to compare Thomas's times with Olympic-level female swimmers because the NCAA races the swimmer competed in were measured in yards instead of meters. One yard is 0.9144 meters, so a 200-yard race is shorter than the 200-meter competition in the Olympics by about 17 meters, for example.

Race Lia Thomas NCAA record 2019 NCAA Championships
200-yard free 1:41.93 1:39.10 1:40.26
500-yard free 4:34.06 4:24.06 4:31.34
1,650-yard free 15:59.71 15:03.31 15:39.22

Harper said the NCAA has had a transgender policy in place for at least 10 years but has not had a transgender woman win a Division I championship during that time. The NCAA rules require transgender female athletes to undergo at least one year of testosterone suppression treatment before they can compete in women's sports competitions. The NCAA has had a transgender woman, Cece Telfer, win in Division II championships during that time.

She said part of the reason transgender athletes have not won more NCAA championships is that transgender women make up a very small percentage of the competitors. Harper acknowledged that transgender women typically have an advantage over biological women and cited height, weight, and strength as the general advantages. She noted that there remain unanswered questions about the extent of some of those advantages.

"Left-handed baseball players have numerous advantages over right-handed baseball players. So per se having advantages doesn't mean that it is unfair to allow two groups to compete against one another," she said. "While trans women definitely have advantages, you have to ask yourself why aren't trans women taking over NCAA sports."

Tommy Lundberg, a researcher and lecturer at the Karolinska Institutet in Sweden, has also conducted research on transgender women competing in sports. He agrees that transgender women have advantages over biological women and argues that the debate is over inclusion versus fairness in sports.

"Due to this advantage of going through male puberty, it is just not possible for women and men to be together. But those men and women can have whatever advantage that they have within their own category," Lundberg told the Washington Examiner. "In some sports such as boxing, there are different categories for things like weight, and those sports are good at selecting out what advantages are so large that they disrupt the meaning of sports."


Thomas competed as a male at the University of Pennsylvania for three years prior to transitioning and moving to the women's team. Lundberg said the difference in performance between the average male and average female is around 12% and that Thomas has not seen a performance drop by that amount since transitioning.

Race Thomas Pre-Transition Thomas Post-Transition
200-yard free 1:39.31 1:41.93
500-yard free 4:18.72 4:34.06
1,650-yard free 14:54.76 15:59.71

Several parents of some of Thomas's peers on the swim team penned a letter to the NCAA that argued the swimmer had an unfair competitive advantage due to being a transgender athlete. Lundberg said the NCAA's transgender rules are not enough to keep transgender athletes from obtaining an advantage in female competitions.

"There's a significant proportion of the advantage that is retained," he said. "And we know this from research that testosterone suppression for 12 months does not remove the male advantage that you acquire through the male puberty, so that's why, currently, fairness and inclusion cannot coexist in a competition. They are mutually exclusive."

The NCAA's rules for transgender athletes differ from Olympic rules.

The Olympic rules for transgender qualification in the Olympic Games are generally set by the national governing bodies themselves, not the International Olympic Committee, according to Harper.

This means that USA Swimming makes the final decision for U.S. athletes, and it bases its standards on the international federation, Federation Internationale De Natation, which currently requires low testosterone levels. There is not enough publicly available information from Thomas to know if these requirements were met.

Harper said the rules could also change by the 2024 Olympics. The IOC recently updated its guidelines for rules on transgender athletes and argued that there should not be testosterone restrictions put on transgender women without further research.

"It will be decades before we have robust peer-reviewed research," Harper said. "If FINA were to follow what the IOC said, then they wouldn't put any restrictions on. But I don't think that will happen."