Dec. 11 (UPI) -- For Democratic presidential candidate Rep. Tulsi Gabbard, D-Hawaii, and Republican Rep. Markwayne Mullin, R-Okla., introduced a bill Thursday tying Title IX protections for female athletes based on "biological sex."
The bill, which attempts to address the issue of transgender women in sports, clarifies that Title IX compliance should be "determined on the basis of biological sex as determined at birth by a physician."
Title IX outlaws discrimination based on sex at any school receiving federal funding. The law has been widely used in promoting the growth of women's collegiate sports, placing them on equal footing as men's sports.
Recently court rulings pointed to the law for allowing transgender women to play on women's sports teams.
"Title IX is being weakened by some states who are misinterpreting Title IX, creating uncertainty, undue hardship and lost opportunities for female athletes," Gabbard, who did not run for re-election to her House seat, said in a statement. "Our legislation protects Title IX's original intent which was based on the general biological distinction between men and women athletes based on sex."
Mullin said in his statement that allowing "biological males" to compete in women's sports diminishes opportunities and a "level playing field" for all women.
"As the father of three girls involved in athletics, I want them to be able to compete on a level playing field," he said. "I am proud to lead this bill that will safeguard the integrity of women's sports and ensure female athletes can compete fairly."
Delaware's Sarah McBride, who recently made history as the first transgender woman to win an election as a state senator, mocked Gabbard for being connected with the bill.
"Tulsi Gabbard: assigned Republican at birth," McBride wrote on Twitter.
LBGTQ rights advocate Charlotte Clymer called the legislation "blatantly transphobic" and accused Gabbard supporters of using trans people as "bargaining chips."
"Usually, when I've criticized Tulsi Gabbard in the past for her heinous record and positions, I've had her fans bombard me with nonsense," Clymer said. "It'll be interesting to see how quiet they remain over this."