The state House voted 81-28 Wednesday to pass the so-called Mississippi Fairness Act. It passed the state Senate last month, 34-9. The bill now heads to Gov. Tate Reeves for approval.
A growing number of states have proposed legislation that would restrict transgender student-athletes from participating in school sports. As of Feb. 26, the ACLU has tracked 25 states considering such bills this year, compared to 18 last year. This week, Wisconsin also introduced a similar bill.
Idaho became the first state to pass a law banning transgender women from competing in women's sports last year. A federal district court suspended the law and it has yet to be enacted.
Mississippi's act is the first of its ilk to successfully pass through both chambers this year. Some have failed in committee, including in South Dakota on Wednesday and in Utah last month.
A similar bill also died in committee in Mississippi last year. Republican state Sen. Angela Hill, who sponsored that bill and the one that passed the House Wednesday, told ABC News she was inspired to introduce the legislation after learning about two girls' championship-winning transgender high school runners in Connecticut, where state policy allows high school athletes to compete as the gender with which they identify. Mississippi does not have a policy regarding transgender high school athletes.
"If we do not move to protect female sports from biological males who have an unfair physiological advantage, we will eventually no longer have female sports," she said.
Hill could not point to any instance of transgender girls competing on girls' sports teams in her state's high schools, but said she has heard concerns from coaches about Mississippi's lack of guidelines.
"This issue is imminent in Mississippi," she said. "We have to make a statement that women matter, female sports matter."
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Following the House passage, Human Rights Campaign President Alphonso David said Mississippi was "on the wrong side of history."
"There is simply no justification for banning transgender girls and women from participating in athletics other than discrimination," David said in a statement. "Like all girls, transgender girls just want to play and be part of a team with their friends. History will not look kindly on this moment in Mississippi."
LGBTQ advocates warn that such bills send a damaging message to transgender youth.
"These dangerous bills are designed to make the lives of transgender kids more difficult while they try to navigate their adolescence," David said.
The Mississippi bill would require any public school and university that is a member of the Mississippi High School Activities Association and NCAA, among other associations, to designate their athletic teams as male, female or co-ed and restrict athletes assigned male at birth from joining female teams. It would not prevent cis women from participating on a male team.
Hill expects the bill to come across Reeves' desk in the coming week or so. The Republican governor has been critical of policies allowing transgender athletes to play women's sports.
He said he was "disappointed" by President Joe Biden's executive order combatting discrimination based on gender identity and sexual orientation, which stated, "Children should be able to learn without worrying about whether they will be denied access to the restroom, the locker room, or school sports."