A few years ago, Beggs began transitioning from female to male.
Before falling to Beggs in the semifinals, Cypress Ranch High School's Kayla Fits, actually told the Dallas Morning News that she was going to take his title.
"It sure as hell didn't stop me from doing what I wanted to do in the past, and it won't stop me from what I want to do in the future", Beggs said.
"He has so much respect for all the girls he wrestles", said Beggs' mother, Angela McNew.
"People think Mack has been beating up on girls ..."
"You put me in front of anybody and I'll wrestle them", he said.
Many parents have been outraged to see their daughters wrestling someone who, effectively, has the strength of a young man.
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Much of the sentiment followed over to his state championship campaign this year, evident in a video of the win which surfaced online, revealing a mix of cheers and boos from the crowd.
Because of a state athletic policy, high school student-athletes must compete as the gender that's on their birth certificate. I can tell the state legislature to change the policy, but I can't tell them to change it right now. But despite Beggs' new gender and use of testosterone, the wrestler continues to wrestle as a female.
When he won the state title Saturday, the boos were overtaken by cheers, not that he lets the reception he receives affect him. The birth certificate rule was approved in 2016 by the University Interscholastic League, the governing body for Texas high school sports. Beggs heads into the State Tournament undefeated at 32-0 this season.
The solitude allowed him to concentrate on the task ahead and perhaps shield him from attacks on social media and occasional insults from the stands - or even other wrestling mats - during meets.
Beggs has compiled a 132-9 record over the last three seasons, and hasn't lost a match in the past two years. Beggs faced only one forfeit this season. Though the UIL has said publicly that it has never received an official request from Beggs or his school asking to wrestle boys.
"The UIL is not in the gender-determining business and schools don't want to be either", UIL deputy director Jamey Harrison told the Associated Press.
Beggs, who was born female as Mackenzie, identifies as a male.