High school athlete Mack Beggs, a transgender boy, competes in a state championship girls wrestling competition, in Cypress, Texas, US, February 24, 2017. Courtesy of Eric Schell/Handout via REUTERS.?[Photo/Agencies]

CYPRESS, Texas－A 17-year-old transgender boy completed an undefeated season by winning a controversial Texas girls' wrestling title on Saturday.

The event was clouded by criticism from those who believe the testosterone Mack Beggs is taking to transition from female to male created an unfair advantage.

The teenager's family said he would rather be wrestling boys, but state policy calls for students to wrestle against the gender listed on their birth certificates.

So the junior from Euless Trinity beat Chelsea Sanchez 12-2 in the 110-pound (50-kg) category to improve to 57-0 and earn the championship.

Beggs fell to his knees after the win as a mix of cheers and boos rained down on him. He then hugged his coach and left the mat.

He had a bit of fun with his fellow wrestlers at the medal ceremony when he counted down from three and all six of the top finishers posed by doing a dab on the medal stand.

Beggs, who reached the state tournament after two opponents forfeited, was dogged throughout the tournament by questions about whether his testosterone treatments made him too strong to wrestle fairly against girls.

He pinned Kailyn Clay earlier on Saturday to reach the final. That was after he beat Taylor Latham and Mya Engert handily on Friday to reach the semifinals.

Beggs' semifinal was halted for a few of minutes because he had a bloody nose, but when the bleeding stopped, the fight resumed.

Not long after, Beggs slammed Clay on the mat and pinned her.

He and Clay shared a long hug before an official raised Beggs' arm to signal victory.

Clay's coach shouted to reporters that she "did not have permission" to talk to them after the final, and the runner-up's parents declined to comment.

Beggs' participation comes at a crucial moment, with the public and politicians debating the growing belief that gender is fluid. Just this week, the Trump administration announced an end to federal protections that allowed transgender students to use facilities based on their gender identity, leaving states and school districts to determine their own policies.

Texas, lawmakers are considering a bill similar to HB2, the North Carolina law that prompted the NBA to move this year's All-Star Game out of that state. If passed, the Texas version would require transgender people to use the bathroom of their "biological sex".

The University Interscholastic League (UIL), which oversees athletics in Texas public schools, enacted the birth-certificate policy on Aug 1.

Attorney Jim Baudhuin tried and failed to get injunctions before both the district and regional meets to prevent Beggs from competing while he transitions because he is taking testosterone.

Baudhuin, who is the parent of a wrestler at another school who has never faced Beggs, told Associated Press earlier this week he doesn't blame Beggs for the situation, but faults the UIL.

Associated Press