The Arizona House of Representatives passed a new bill that if signed into law would ban transgender female athletes from participating in school sports.
The "Save Women's Sports Act," introduced by Republican Rep. Nancy Barto, would require interscholastic and intramural sports sponsored by educational institutions to explicitly designate sports as for males or females based on a persons' biological sex.
"This bill is about fairness. That's it. What is fair on the field, the court, the track, and in the pool," Barto said in a statement to ABC News.
House Bill 2706 states that if disputed, "a student may establish the student's sex by presenting a signed physician's statement that indicates the student's sex" and an analysis of the student's DNA.
The bill was first introduced on Feb. 3 and passed in the House one month later along party lines 31-29 after an emotional hours-long debate on Tuesday.
Barto cited the biological differences between males and females from lung capacity and muscle mass to testosterone levels that she said give men "an undeniable physical advantage over women in sports."