A boy winning a girls’ wrestling competition is likely not what Texas’s University Interscholastic League (UIL) expected when it set up transphobic rules for school sports. But it’s exactly what’s happening.

According to UIL’s rules, competitors in Texas high school events must play in the league that aligns with the gender marked on their birth certificate, and boys can’t wrestle girls or vice versa. At the same time, changing a gender marker on a birth certificate can be an arduous process; in Texas, it requires obtaining a court order — one that, according to the National Center for Transgender Equality, not all judges are willing to give.

The problem for Mack Beggs, a 17-year-old transgender boy, is his birth certificate still misgenders him. As SportsDay reported, this means Beggs has been forced to compete in girls’ wrestling competitions, even as he takes testosterone that may give him an advantage in the arena. And on Saturday, he won his region’s 110-pound championship for girls — in an example of how anti-trans rules can backfire.

He wants to compete in the boys’ league, but transphobic rules won’t let him

Beggs began taking testosterone treatments in October 2015. Since then, he’s tried to get on the boys’ wrestling league on behalf of his high school, Euless Trinity. But the league’s rules don’t allow him to, because they still misgender him as a girl.

Yet they do let him compete in the girls’ league because the testosterone he’s taking — effectively a steroid — is “dispensed, prescribed, delivered, and administered by a medical practitioner for a valid medical purpose.” (Gender dysphoria, a state of emotional distress caused by how someone's body or the gender they were assigned at birth conflicts with their gender identity, is an acknowledged medical condition, and it’s often treated by transitioning.)

This has caused some consternation among Beggs’s competitors, who essentially say he’s cheating and putting girls at risk of physical harm by being allowed to take his testosterone and compete. In his final regional match, Beggs won by default because his opponent forfeited. The win means Beggs, who’s been wrestling since before his transition, remains undefeated this season.

His opponents have sued the league to stop him from competing

Beggs’s opponent hoped to stop the latest match from ever taking place by suing UIL to prevent him from competing. As attorney and wrestling parent Jim Baudhuin told SportsDay, Beggs’s competitors believe he has an unfair advantage, even though they say they have no problem with Beggs’s gender identity.

“I respect that completely, and I think the coaches do,” Baudhuin said, before going on to misgender Beggs. “All we’re saying is she is taking something that gives her an unfair advantage. It’s documented. It’s universal that it's an unfair advantage.”

Diane Ehrensaft, a psychologist who co-founded the Child and Adolescent Gender Center in California, said that testosterone can build muscle mass, but the actual changes can vary from person to person. “Not every kid I've seen who has gone on testosterone has added muscle mass,” she said to SportsDay.

Sports remain a battleground for trans rights

If testosterone gives Beggs an advantage in the girls’ league, the UIL, athletes, and parents can only blame the league’s transphobic rules for the consequences. If the UIL simply allowed trans people to compete in the league that aligns with their gender identity, this wouldn’t be a problem to begin with.

Yet sports, particularly at the high school level, remain a controversial battleground for trans issues. Much of the debate is typically about whether letting trans girls compete in girls’ sports leagues would give the trans girls an advantage. (For example, until last year the International Olympic Committee still imposed some outdated hurdles on trans athletes by requiring surgeries that all trans people may not obtain.) A recent study, however, found that since hormone therapy for trans women decreases muscle mass, it erases at least some advantages trans athletes would have — to the point that trans distance runners lose their edge over cisgender distance runners after a year of hormone therapy.

There are also hot-button issues about bathrooms and locker rooms, based in large part on an unfounded myth that letting trans people use the bathroom or locker room that aligns with their gender identity would put others at risk. Multiple investigations have found no evidence of increased public safety risks if trans people are allowed to use a facility that aligns with their gender identity.

But the concerns remain, leading some leagues to keep transphobic rules on their books. So in Texas, Beggs is, despite being a boy, continuing to compete in the girls’ league — and his opponents are upset.