Transgender swimmer Lia Thomas failed in her challenge against rules that stop her from competing in elite women’s races because judges ruled she did not have standing to bring the case.

The Court of Arbitration for Sport panel of three judges dismissed Thomas’ request for arbitration with the World Aquatics governing body, in a ruling released Wednesday.

World Aquatics banned transgender women who have been through male puberty from competing in women’s races. It also created an “open” category for which transgender athletes would be eligible.

Thomas had asked the sports court in Switzerland to overturn the rules approved in 2022 that she said were invalid, unlawful and discriminatory.

Thomas called the CAS’ decision “deeply disappointing” in a statement provided by her legal team. “Blanket bans preventing trans women from competing are discriminatory and deprive us of valuable athletic opportunities that are central to our identities.” Thomas said the decision should be viewed as a call to action for trans women to “fight for our dignity and human rights.”

Athlete Ally founder and executive director Hudson Taylor called it a “sad day for sports and for anyone who believes that trans athletes should have the opportunity for their experiences of discrimination to be heard and adjudicated like everyone else.”

Gay & Lesbian Alliance Against Defamation (GLAAD) president/CEO Sarah Kate Ellis said in a statement that Thomas deserves a chance to participate in her sport like all human beings who work hard and follow their dream.

“World Aquatics continues to spread disinformation about transgender people as a distorted way to ‘protect women,’” Ellis added. “Transgender women are women and all athletes who want to play and follow the rules should have a chance to do so.”

Thomas swam for the University of Pennsylvania and won an NCAA title in meets that are outside the World Aquatics competitive system, in which she was not registered.

The world swim body argued to CAS that Thomas was not a member of its member federation USA Swimming when the legal case was started. She also had not competed in female events “for the purpose of qualification or selection” for World Aquatics competitions, such as the Olympics or world championships.

“The panel concludes that she lacks standing to challenge the policy and the operational requirements in the framework of the present proceeding,” the court said in its ruling.

In January, the ruling said, USA Swimming granted her request for “self-identity verification” as part of its policy on athlete inclusion.

The judges said USA Swimming had no authority “to modify such scope of application” of the world governing body’s rules.

World Aquatics said it welcomed the CAS decision in a case “we believe is a major step forward in our efforts to protect women’s sport.”

“World Aquatics is dedicated to fostering an environment that promotes fairness, respect, and equal opportunities for athletes of all genders and we reaffirm this pledge,” the governing body based in Lausanne said in a statement.

Swimming’s policy on transgender athletes was followed by other top-tier Olympic sports, track and field, then cycling, in excluding from women’s events those who have potentially gained lasting physical advantages from male puberty.

The International Cycling Union noted last year “it is also impossible to rule out the possibility that biomechanical factors such as the shape and arrangement of the bones in their limbs may constitute a lasting advantage for female transgender athletes.”

Thomas was represented at CAS by Toronto-based Tyr, the legal firm that has represented two-time Olympic champion runner Caster Semenya. Semenya is excluded from running in her specialist 800-meter event by World Athletics rules on athletes with differences in sex development who have elevated levels of testosterone.

The CAS judges declined World Aquatics’ request for Thomas to pay its legal costs and other expenses incurred in the case.

The judging panel included two of the highest-profile CAS arbitrators: Thomas selected Richard McLaren, the Canadian investigator who helped prove the Russian doping scandal at the Sochi Olympics; and World Aquatics chose Ulrich Haas, a German law professor who helped judge celebrated cases involving Manchester City and Grand Slam tennis champion Simona Halep.

The CAS panel, which held a hearing in March, was chaired by a Paris-based Spanish arbitrator Carmen Núñez-Lagos.

The ruling was dated Monday, five days before the U.S. trials meet for the Paris Olympics starts in Indianapolis.