The Republican-controlled Arizona House of Representatives passed a bill prohibiting transgender females from participating in girls’ sports, despite claims from opponents that it promotes discrimination.

The House voted on a party-line vote of 31-29 to approve the bill, which would require interscholastic and intramural teams to classify sports as co-educational, male, or female, based on an athlete’s assigned sex at birth. Teams or sports classified as “female” would be closed to “students of the male sex.”

The law would apply to both public and private schools, as well as community colleges and universities.

Under the bill, any student or team who believes they missed out on athletic opportunities because of a transgender person’s presence on a school team would be allowed to sue for damages. The bill would also allow opponents or officials to dispute an athlete’s gender, forcing that athlete to take a genetic test in order to “prove” that their female identity matches their biological sex at birth.

Barto’s bill previously would have required students whose gender was questioned — regardless of whether they were transgender or not — to get a sworn statement from their doctor’s office detailing the student’s genetic makeup, “internal and external reproductive anatomy,” and “normal endogenously produced levels of testosterone.” But Barto amended the measure to remove the sworn statement and the references to anatomy, leaving only the genetic test, reports The Hill.

Related: Elizabeth Warren calls Arizona GOP’s proposed ban on transgender athletes “cruel”

The bill’s sponsor, Rep. Nancy Barto (R-Phoenix), argued that her measure was necessary to prevent cisgender female athletes from missing out on scholarships or titles. Although no such incident has occurred in Arizona, Barto cited a recent federal lawsuit brought by three female athletes in Connecticut who claim they were denied opportunities after losing to a transgender athlete.

“Males should participate with males and compete against males, and females should compete against females,” Barto told Fox News. “Recent research actually verifies that even with cross-sex hormones, men have an unequivocal advantage. They’ve got stronger bones, they’ve got greater lung capacity.

“Shotputs are heavier for boys. Girls’ basketballs are smaller,” she added, providing additional examples of how biological males have an advantage over cisgender females. “It makes a difference.”

Interestingly, although lawyers from Alliance Defending Freedom, representing the three Connecticut student-athletes in the lawsuit cited by Barto claim that cisgender women are at a disadvantage when competing against transgender athletes, one of the plaintiffs, Chelsea Mitchell, recently won the Connecticut state championship titles in the long jump, 300-meter run and 55-meter dash, defeating transgender athlete — and former state champion — Terry Miller in the latter two events.

“Having separate boys’ and girls’ sports has always been based on biological differences, not what people believe about their gender, because those differences matter for fair competition,” ADF attorney Christiana Holcomb said in a statement at the time the lawsuit was filed. “And forcing girls to be spectators in their own sports is completely at odds with Title IX, a federal law designed to create equal opportunities for women in education and athletics.”

But Arizona Democrats have significant reservations about the bill, including that it could open the door for any losing athlete or team to contest game outcomes or preemptively hamstring or waylay their opponents by lodging a complaint alleging someone is transgender — even if they know the athlete in question is not.

Further, they argue, the measure is invasive and humiliating, not only for transgender female athletes, but to cisgender female athletes who find themselves targeted by people acting in bad faith. For instance, when the bill was debated in committee, Rep. Alma Hernandez (D-Tucson) noted that she, as a “tomboy,” could potentially have been targeted and forced to submit to a genetic test had such a law existed when she was a teenager.

Opponents also claim the proposed law would effectively intimidate transgender athletes from withdrawing from sports altogether, as competing on a boys’ team not only disrespects their gender identity, but potentially puts them at risk of physical and verbal abuse or harassment from male teammates or competitors.

Democrats have already dubbed the bill the “Show me your genitals” bill because of now-deleted provisions requiring a physical exam by a doctor.

“I mean, if they want to debate genitals, I guess we’ll see,” Rep. Isela Blanc (D-Tempe) said. “We’re talking about kids in sports that range in athletic ability, height, weight, age. And it’s all to go after transgender girls. It makes no sense. It’s completely wrong, inhumane, unkind, inappropriate and just mean-spirited.”

The measure now heads to the State Senate, where it is expected to be approved. Gov. Doug Ducey (R) has not yet weighed in on the bill.

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