Sports must be ‘a level playing field’: Michael Phelps weighs in on trans UPenn swimmer

"There is, as you know, certain amount of controversy around the University of Pennsylvania college swimmer by the name of Lia Thomas. And there are some people who are questioning her, I'm not sure what the right word, is her right just to swim on a woman's team. She's transgender. What do you make of that?" Amanpour asked.

"And she's obviously doing exceptionally well. She also has been taking testosterone suppressants, but nonetheless does much better, according to the records, than her female contestants. What do you make of this particular situation?" She continued.

"I mean, look, like, I will say I can talk from a standpoint of doping, I don't think I have competed in a clean field in my entire career," Phelps said. "So, I think this leads back to the organizing committees again, because it has to be a level playing field."

"I think that's something that we all need, because it's — like, that’s what sports are. And, for me, I don't know where this is going to go. I don’t know what's going to happen. I believe that we all should feel comfortable with who we are in our own skin. But I think sports should all be played an even playing field. I don’t know what that looks like in the future. But it’s hard. It's a really — honestly, I don’t know what to say," he continued.

"It’s complicated," Amanpour added.

"It's very complicated. And, you know, this is this is my sport. This has been my sport my whole entire career. And I — honestly the one thing I would love is everybody to be able to compete on an even playing field. That's all I can say," Phelps concluded.

Thomas came into the spotlight at the beginning of December, after beating all of her biological female competitors at a three-day meet in Akron, Ohio , where numerous pool, meet, and national records were broken.

In one race, the 1650 freestyle final, Thomas came in first, beating the second place finisher by a whole 38 seconds.

One of Thomas' teammates spoke out following the event, stating that a large number of Thomas teammates did not like the idea of her competing against biological women.

"Pretty much everyone individually has spoken to our coaches about not liking this. Our coach [Mike Schnur] just really likes winning. He's like most coaches. I think secretly everyone just knows it's the wrong thing to do," said the athlete, speaking by telephone with Outkick on the condition of her anonymity.

Some of Thomas' teammates had considered boycotting their final home meet of the season, but decided against the action over fears that the display would prevent them from competing in the Ivy League championship in February.

In late December, a veteran USA swimming official resigned after more than 30 years officiating swim meets at the US level, telling Fox News at the time that she had resigned "days ago," saying "I can't do this," and "I can’t support this."

"Bodies swim against bodies; gender identities don't swim ... Lia [Thomas] should swim against Lia, not against women," said Millan.

"... Men swim 8-12 percent faster then women. Men have a larger lung capacity, skeleton, circulatory system, heart, and nothing that Lia did by taking a year off to take testosterone-suppression drugs – that does not change Lia's body," she continued.

"So, every time Lia jumps into the pool, it is a man who is competing against women. That is grossly unfair ... he is going to be wiping out women's Olympic records, and it's not right for woman swimmers, and it's certainly horrible for girls who are in the sport; they don't matter."