Transgender high school wrestler Mack Beggs is used to winning on the mat, but now, off the mat, the undefeated athlete who recently won the Texas state girls title may have scored his biggest victory yet.

Beggs was born female but began transitioning from girl to boy two years ago – including testosterone injections – and has been fighting to compete against boys. This spring, he will get his chance thanks to USA Wrestling’s new transgender policy. Unlike the University Interscholastic League, which sets the rules for high school competition in Texas, USA Wrestling will not require athletes to compete in the division according to their gender at birth. In fact, the new policy requires those transitioning from female to male to compete in the boys’ division.

“Those who transition from female to male shall only be eligible to compete in the male category without restriction,” USA Wrestling’s new policy states.

The policy, which was passed earlier this month, is loosely based on guidelines set out by the International Olympic Committee in November 2015. The IOC’s guidelines lessened the restrictions and stipulations placed on transgender athletes wishing to compete under the opposite gender identification written on their birth certificates. For example, instead of having to wait to compete until some years after full gender reassignment surgery, prospective athletes need only comply with blood test procedures to ensure their hormones are within acceptable limits.

In the case of post-pubescent individuals transitioning from female to male, though, USA Wrestling waives any hormonal requirements and states that the athlete need only to have “declared that his gender identity is male” to compete against boys.

“We didn’t call them, they called us,” Beggs’s grandmother, and legal guardian, Nancy told the Dallas Morning News about how she and her grandson learned of USA Wrestling’s new policy. “[They] said, ‘We need to make sure Mack is compliant. Having watched everything we realize how important this is to Mack.’ ”

Beggs, 17, will compete in the Greco-Roman discipline this spring at USA Wrestling events, the newspaper reports.

The contests will finally pit Beggs against boys, which is what he wanted all along. Texas’s UIL, however, would not allow it as long as he wrestled at Trinity High in Euless. Unlike USA Wrestling’s policy, the UIL requires athletes to compete under the gender listed on their birth certificates. The rules-making authority also has a set of hormonal criteria athletes must meet and Beggs, who is taking testosterone supplements, never tested high enough to cross a threshold needed to qualify for the boys’ tournament, USA Today reports.

UIL’s refusal to allow Beggs to compete as his self-identified gender generated an uproar in the community, where many complained his continued participation in the girls’ tournament was unfair.

“She’s standing there holding her head high like she’s the winner,” Patti Overstreet, a mother of a wrestler in the boys’ division, told the Post’s Kent Babb directly after Beggs clinched the girls state title Feb. 24. “She’s not winning. She’s cheating. … I don’t care what sex you are. Don’t go on the mat with enhancement if my kid can’t.”

Others have been more sympathetic to Beggs’s situation, but still found his participation in the competition unfair.

“The 16 girls who are in bracket have been put in a very, very unfair situation because of the grown-ups,” an attorney, James Baudhuin told Babb. On behalf of one of Beggs’s competitor’s father, Baudhuin filed a lawsuit last month against the UIL about Beggs’s inclusion in the girls’ division.

“To me, this is a complete, abject failure of leadership and accountability from the people who regulate sports in Texas,” he continued. “They’re doing wrong by Mack, and not just these 15 girls but all the other girls she wrestled all year.”

Against whom Beggs will wrestle in high school next season when he’s a senior remains unanswered. Baudhuin told Babb the suit he filed remains in court. Meanwhile, the UIL said late last month that it will consider revising its current rules, which could mean Beggs could begin wrestling in the boys’ division in his high school matches.

“It’s only getting started,” Beggs’s grandmother Nancy told Babb, perhaps presciently, as she watched her grandson begin his state tournament last month. “Mack is ready for it.”