Upon returning to the team, the female swimmers were surprised to find that Thomas would indeed be using their locker room, which led to feelings of emotional distress among the plaintiffs.

This legal action is part of a growing scrutiny of elite colleges regarding issues of fairness in women's sports and the implications of Title IX.

The swimmers allege they were discouraged from voicing their concerns, facing threats of reputational damage and career repercussions for speaking out against Thomas's inclusion.

Former competitors of Thomas have described their experiences as traumatic, feeling discomfort and fear when competing against her, particularly in shared locker rooms.

On February 5, 2025, three former University of Pennsylvania female swimmers—Grace Estabrook, Ellen Holmquist, and Margot Kaczorowski—filed a lawsuit against the NCAA, Ivy League, and their universities, challenging transgender swimmer Lia Thomas's participation in women's sports.

Lia Thomas, who transitioned from Will Thomas, began competing with the women's team in Fall 2021, despite initial assurances that she would not share a locker room with the female athletes.

The lawsuit, represented by attorney Bill Bock, claims that the plaintiffs were forced to compromise their opportunities, fairness, and safety due to the current policies regarding transgender athletes.

The lawsuit coincides with President Trump's recent executive order that restricts transgender women from participating in women's sports, reflecting a broader legal trend against trans rights.

In the wake of these developments, Georgia's state Senate has passed a bill requiring athletes to compete based on their biological sex, potentially making it the 26th state to enact such measures.

NCAA President Charlie Baker acknowledged the concerns of female athletes during a Senate hearing, emphasizing the need for accommodations for those uncomfortable sharing spaces with transgender individuals.

The lawsuit seeks class-action status for 206 female athletes who competed in the 2022 Ivy League Swimming and Diving Championships, targeting Harvard for hosting the event where Thomas won multiple titles.

Kaczorowski highlighted the importance of this case for future generations of female athletes, stressing the need to protect women's sports records.