The world's first male transgender professional boxer Patricio Manuel has said it would be "dehumanising" to exclude trans athletes from competitive sport as it had transformed many lives.

Debate is raging around the world over the participation of male-to-female trans athletes, who have allowed to compete in the Olympics since 2016 if their testosterone levels remain low enough for a year.

The International Olympic Committee is working on new guidelines for them to participate in the Tokyo 2020 Games.

"A lot of the immediate pushback is usually from people who haven't done adequate research," said Manuel. "I don't feel that trans athletes have any specific advantages or disadvantages."

Manuel, who was raised as a girl in California, fell in love with boxing at 16 when his grandmother took him for his first lesson and credits the sport with helping him deal with his internal struggle over his gender identity.

"I was completely disconnected from my body; I was experiencing massive gender dysphoria," said Manuel, referring to the condition where someone feels distress because their gender identity does not match their physical body.

Patricio Manuel.
Image: Everlast

"I was attracted to the masculinity of the fighters and I knew that boxing (would) make me feel better about myself."

Manuel, 34, made boxing history in December in his first professional fight as a man, when he beat Hugo Aguilar on a Golden Boy Boxing fight card, at a time of fierce debate over the participation of trans athletes in competitive sports.

While many leading athletes, including British Olympians Sharron Davies and Paula Radcliffe, have condemned the inclusion of male-to-female trans athletes as unfair, scant attention has been paid to female-to-male athletes such as Manuel.

"No one expects us to win," Manuel said. "To my critics, my win was the biggest statement in itself.

"(It is) so dehumanising to exclude people from a whole arena that has been shown to be so transformative for so many lives out there," Manuel said.

A five-time USA female national amateur boxing champion, Manuel began his transition to a man - with hormones and gender-affirming surgery - shortly after being eliminated from the 2012 U.S. Olympic Trials due to a shoulder injury.

"That downtime really forced me to look at myself as a person rather than just as an athlete," he told the Thomson Reuters Foundation by phone from Los Angeles.

"But the biggest issue for me was that I wasn't a woman ... I felt like I was a man and needed to live my life as a man."

In 2016, Manuel made headlines around the world in his first fight as a man when he faced Adan Ochoa - on paper a much more experienced boxer - and won.

"It was a difficult match, but more than anything it was important for me to prove that I was still a winner," he said.

"I'm used to winning. I'm not in this sport just to participate - I'm in it to win."

His global status was affirmed on Thursday when the boxing brand Everlast announced that Manuel had been chosen as one of the faces to front its Be First advertising campaign, alongside fellow fighters Jinji Martinez and the Balderas family.

Temporarily sidelined once more by injury, Manuel knows that as a relatively older athlete time is against him. He aims to get back in the ring later this year or early next.

"I know I'm not done," he said. "I still want to see how far I can take this sport."