Claressa Shields cited sexism she experienced during her boxing career as one reason she signed with the Professional Fighters League.

In an interview with TMZ Sports, Shields called boxing "so sexist," pointing to how much money she earned compared to male boxers.

"These men are fighting for multiple millions that haven't accomplished half of what I accomplished, but I'm supposed to just be happy?" she said. "Like yeah, go ahead and pay me $300K and then offer me $150,000 for the next fight?"

She said she "[did] everything I can do in boxing and I still haven't made $1 million for a fight." She also contended that networks would say her number of followers on social media wasn't big enough for her to fight on pay-per-view.

A move to the PFL allows Shields the opportunity to collect the $1 million prize she seeks. That's how much Kayla Harrison earned when she won the PFL women's lightweight championship in December.

Shields is a two-time Olympic gold-medalist boxer in the middleweight class, and she was a perfect 10-0 as a professional before transitioning to MMA. The 25-year-old is slated to compete in the PFL's 2022 season, using 2021 to ease her way into cage fighting.