Utah State University aims to join lawsuit challenging trans sports participation

Utah State University has filed a motion to join an ongoing lawsuit that aims to challenge the policies of the Mountain West Conference, which allow transgender students to play on the team that aligns with their gender identity.

Several volleyball teams -- including Utah States' team -- have refused to compete against the San Jose State University team, which the plaintiffs say has a transgender player. The Nov. 18 Utah State court filing states that the team's refusal to compete was "due to concerns of fairness and to communicate that they do not agree with the [Transgender Participation Policy] and hold strong personal and political beliefs that transgender women should not be permitted to compete in women’s sports."

A San Jose State University spokesperson told ABC News that it will not address or confirm the gender identity of any student athlete due to federal privacy protections, but argues that all athletes are in full compliance with NCAA and Mountain West rules and regulations.

ESPN reports that the student, who is playing in her third season with the team, has never publicly stated that she is transgender.

"It is disappointing that our SJSU student athletes ... have been denied opportunities to compete," a San Jose State spokesperson said in a statement. "We remain committed to supporting our student-athletes through the challenges the team has faced and in their ability to compete in an inclusive, fair, safe and respectful environment."

Teams who refuse to participate in a match against a team officially forfeit the game and are charged with a loss "for the purpose of Conference records, standings, tie-breaking formulas and MW championships participation," according to Mountain West Conference policies.

Utah State is arguing that the decision to forfeit the matches should not count as a loss, and that the conference's policies harmed the team's winning percentage and chances at advancing competitively.

Other plaintiffs argue that their First and Fourteenth Amendment were violated, along with the Title IX protections, by the policy allowing trans players to participate.

The Mountain West Conference abides by the participation standards of the National Collegiate Athletic Association (NCAA). The NCAA transgender participation guidelines -- which align with the Olympic standards -- vary from sport to sport. As it stands, transgender student-athletes typically need to document sport-specific testosterone levels throughout the competition season.

Utah State and the Mountain West Conference did not respond to ABC News' requests for comment.

The transgender community – which makes up less than 1% of the adult population and about 3% of the high school aged population – has been the target of political campaigns for Republicans, many of whom have backed a wave of legislation restricting their bathroom use, sports participation and access to gender-affirming health care.

Research on whether transgender women have an advantage physiologically remains up for debate, according to researchers.

One study in the British Journal of Sports Medicine found that the athletic advantages of the 46 trans women over their cisgender counterparts declined with feminizing therapy. However, this study also found they had a 9% faster mean run speed than cisgender women after a one-year period of testosterone suppression.

Meanwhile, a different study in the American Journal of Sports Medicine found that there is not yet any direct or consistent research suggesting transgender women have an athletic advantage at any stage of their transition.

Restrictions on hormone levels have impacted athletes with differences in sex development, such as those who are intersex or have naturally high testosterone levels.

ABC News' Abby Cruz contributed to this report.