DUARTE, Calif. (FOX 11) - Pat Manuel is a heavy hitter, fast on his feet, focused and determined.
Manuel started fighting at the age of 16, but at the time, he was a completely different person.
"I'm a competitor. I'm always looking to take myself to the next level. I was an excellent female fighter. One of the best in the world," Manuel told FOX 11.
Manuel was a female fighter who felt trapped in the wrong body.
"I was told I was a girl growing up my entire life, but really in my head, I was a boy," Manuel said. "...But puberty and society was like no, this is your lot, this is who you are and I had no idea that there were any other options."
Despite the inner turmoil, Manuel became a fierce female fighter, winning numerous national championships. But during the 2012 Women's Olympic trials, Manuel suffered a serious injury.
"It was emotionally painful. I had worked so hard to get to the Olympics and just to have it go out like that, it was pretty heart-crushing."
After a deep depression, Manuel decided it was time to make a change.
"I realized that I had been lying to myself for so long and lying to other people for saying I was a woman and I decided at that moment that I didn't want to live that lie anymore. I wanted to live myself as I really, truly felt and I wanted to live as a man."
It wasn't an easy transition. It involved hormone therapy and sexual reassignment surgery.
After four years of being away from the sport, USA boxing granted Manuel a license in the male division.
For the first time in U.S. history, a boxer has fought as both a woman and a man. Manuel said he's never been happier.
"You just have to be yourself no matter what the risk. No matter what people are going to say... Ultimately being your authentic self is worth fighting for."