MADISON, Wis. (AP) — Republican-backed bills that would prohibit transgender athletes in Wisconsin from participating in girls’ and women’s sports teams met with broad opposition Wednesday during their first public hearings before legislative committees.

More than 30 groups opposed the measures, including the Wisconsin Interscholastic Athletic Association, which regulates high school sports, the University of Wisconsin-Madison, the statewide teachers union, the ACLU, the State Bar of Wisconsin’s civil rights and liberties section, the LGBTQ advocacy group Fair Wisconsin, Planned Parenthood and the Wisconsin Coalition Against Sexual Assault.

There were no registered supporters of the bills ahead of the hearings.

“This is a matter of equality and justice,” said the bill’s co-sponsor Rep. Barb Dittrich, of Oconomowoc. “This legislation is a matter of fairness based on facts.”

Even if the bills were to pass the GOP-controlled Legislature, Democratic Gov. Tony Evers would likely veto them. Evers, a former school administrator and state superintendent for education, this week called the bills a “solution seeking a problem that doesn’t exist” and reiterated that he stands with transgender students.

The proposals are part of a nationwide movement targeting transgender people, particularly athletes.

Lawmakers in more than 30 states, mostly Republican controlled, have considered sports participation bans, and they’ve become law in Alabama, Arkansas, Mississippi, Tennessee, Montana and West Virginia after Idaho enacted one last year. Other states, including Kansas and North Dakota, passed bans only to have them vetoed by the governor.

The Wisconsin bills would allow students to join teams only that correspond to their biological sex as assigned by a doctor at birth, unless the sport is classified as “coed.” It would apply to public and private schools, as well as the University of Wisconsin and technical colleges.

Supporters argue that the bills are designed to address the issue before it becomes a problem. They argue that transgender girls have an unfair physical advantage, and that passing the bill would ensure that girls have a level playing field while preserving competitive achievements and scholarships.

Female athletes “simply cannot compete with biological males in athletics,” bill backer Republican Rep. Janel Brantdjen said in prepared testimony.

“If we follow the science, the only conclusion we can reach is that males have a tremendous and insurmountable advantage in sports,” Brandtjen said.

Opponents say such proposals are cruel and discriminatory, and that they violate Title IX of federal education law prohibiting sexual discrimination as well as U.S. Supreme Court rulings. They also argue that such bans would further marginalize vulnerable students and hurt the state’s economy by making it more difficult to recruit athletes and businesses.

“You call this protect women in sports act?” said Democratic Rep. Sondy Pope, a member of the Assembly Education Committee. “Transgender women are women. You are singling out which women you want to protect, which I find confusing.”

In written testimony prepared for the hearing, the University of Wisconsin-Madison said that if the measures are enacted, the school wouldn’t be in compliance with NCAA’s trans-inclusive policies. The bill also would jeopardize the state’s ability to host events and tournaments because the NCAA has said it will consider actions that discriminate against certain athletes.

“Passage of this legislation would have serious financial and reputational consequences for Wisconsin college teams,” the university said in opposition to the proposal.

The Wisconsin Interscholastic Athletic Association enacted a policy similar to that of the NCAA’s requiring transgender female athletes to complete one calendar year of medically documented hormone replacement therapy, and get a doctor’s signature and parental consent before they can compete on a girls’ team.

WIAA spokesman Todd Clark said the association hasn’t received any complaints about transgender athletes competing in high school sports.

A growing number of state high school athletic associations in the U.S. have enabled transgender athletes to play on teams based on their gender identity.

A federal court blocked enforcement of the law in Idaho. In Connecticut, several girls are challenging a state law that allows transgender athletes to participate in female sports.