Transgender swimmer Lia Thomas is so well-endowed that female swimmer Riley Gaines had “refrain from looking” at Thomas in the locker room they shared during a meet.

In a new podcast with Bill Maher dropping Sunday, Gaines, an advocate for women’s sports, repeatedly declined to estimate Thomas’ size but explained it is in proportion to the frame of a “6-foot-4 male.”

Gaines tied against Thomas in the 2022 NCAA Championships and since has become an outspoken activist against biological men in women’s sports – saying it was unfair and that changing alongside Thomas in the locker room was weird and awkward.

Some swimmers undressed in the janitor’s closet to avoid Thomas.

“That was a situation I tried to refrain from looking at entirely,” Gaines said, according to a transcript of the Club Random podcast obtained first by the Daily Mail.

A photo of swimmer Riley Gaines.
Swimmer and women’s sports advocate Riley Gaines said she had to “look away” from the size of trans swimmer Lia Thomas’ endowment in the women’s locker room.AP
“We can’t unsee it. Being in that space with a male, it’s like a bad car wreck.”

Maher repeatedly grilled Gaines to detail the genitalia of Thomas, who joined the University of Pennsylvania women’s swim team after competing for three years on the men’s squad.

“I was trying to run away from this question,” Gaines answered.

A photo of Lia Thomas.
When asked by Bill Maher how big Lia Thomas’ endowment was, Riley Gaines said it was in proportion to a 6’4″ male.Paul Rutherford-USA TODAY Sports
“6-foot-4 male. Use your imagination,” she said.

Gaines believes biological males’ greater strength and endurance make competition with women unfair – and her view has stirred controversy.

A photo of trans swimmer Lia Thomas.
In a new podcast with Bill Maher, swimmer Riley Gaines said she had to “look away” from trans swimmer Lia Thomas’ “well-endowed” genitalia in the locker room.USA TODAY Sports
In April, Gaines was “ambushed and physically hit” by a mob of trans-rights protesters who stormed her speech about protecting women’s sports at San Francisco State.

By the conclusion of Thomas’s swimming career at UPenn in 2022, Thomas’ rank skyrocketed from 65th for men to 1st in the female 500-yard freestyle, and from 554th for men to 5th for women in the 200-yard freestyle.

A photo of Riley Gaines.
Swimmer Riley Gaines has led the fight against biological men who identify as women in women’s sports, saying it is unfair.Elliott Hess
“I think even using the term trans woman is giving Thomas some of our languages as women,” Gaines said in the podcast. “I think trans women is a subset of male. I do not believe trans women are women.”

Last week, former UPenn swimmer Paula Scanlan told The Post she “had nightmares for weeks” after sharing a locker room with Thomas.

At the March 2022 championship in Atlanta, Thomas won the women’s 500-yard freestyle, becoming the first trans woman to claim a national title in swimming and becoming a symbol of trans athletes.

A photo of Lia Thomas.
Lia Thomas has never addressed the concerns of the female swimmers who say that biological men in women’s sports are unfair.NCAA Photos via Getty Images
Trans rights activists say trans women are real women and must be included in sports.

Gaines, who comes from Tennessee and swam for the University of Kentucky team, said America needs “more masculine men” and praised World War II veterans.

“That’s the last time we had strong men,” she said.

A photo of Lia Thomas.
By the conclusion of Thomas’s swimming career at UPenn in 2022, Thomas’ rank had moved from 65th on the men’s team to 1st on the women’s team in the 500-yard freestyle.Brett Davis-USA TODAY Sports
“Think about this: 1940s, World War II. Men lied about their age to get in to enlist. Now, in 2023, we have men lying about their sex to get into women’s sports or women’s prisons or domestic shelters or sororities or bathrooms, locker rooms.”

She blames society for rebranding “masculinity as toxic and bad and undesirable.”

In June, the world swimming’s governing body effectively banned transgender women from competing in women’s events.

The International Swimming Federation members widely adopted a new “gender inclusion policy” that only permits swimmers who transitioned before age 12 to compete in women’s events.

The organization also proposed an “open competition category.”