Former Massachusetts Gov. Charlie Baker in the Hot Seat in NCAA Gender Policy Battle

Charlie Baker continues to come under fire as GOP senators and women’s rights groups pressure the former Massachusetts governor to allow only “biological females” to compete in NCAA women’s sports.

Baker, who became NCAA president after leaving Beacon Hill last year, received a letter Tuesday from 23 GOP senators urging him to update NCAA policies on student-athlete participation as the Biden-Harris administration implements Title IX changes.

“The science is clear,” said the letter, led by U.S. Sen. Marsha Blackburn, R-Tennessee, and signed by 22 Republican colleagues. “Men have an innate athletic advantage over women due to their anatomy and biology.”

The new Title IX rules went into effect earlier this month after the Biden-Harris administration this spring overturned a landmark 1972 law that banned sex discrimination at institutions receiving federal funding.

The updated regulations include protections for LGBTQ+ students, an expanded definition of sexual harassment in schools and colleges, and safeguards for victims.

In their letter, the Republican senators stressed that they believe the NCAA “has continued to take no steps to protect” female student-athletes. Title IX rewrites have been enacted in just 24 states, and Republican attorneys general have fought the legislation in 10 lawsuits to block them in 26 other states.

“Whenever we compare the athletic achievements of adult men with the athletic achievements of adult women in disciplines requiring endurance, muscular strength, speed and power, men prevail, outperforming women by 10 to 30%,” the letter reads.

Education Secretary Miguel Cardona highlighted on Aug. 1 how the legislation “clarifies that Title IX’s prohibition on sex discrimination covers all forms of discrimination based on sex.”

“It is unacceptable for any student to have to give up her dreams of college because she is pregnant,” he said, “and it is unacceptable for any student to face discrimination or harassment simply because of who she is.”

The Republican senators also noted in their letter that the National Intercollegiate Athletic Association’s Board of Governors approved a policy in April banning men from participating in women’s sports.

That came before a ruling by the Court of Arbitration for Sport that found that Lia Thomas, the swimmer who became the first openly gay athlete to win a Division I national championship, had no legal standing to challenge World Aquatic’s policy that barred Thomas from competing in the Olympics.

“Men may have innate athletic abilities, but they have no advantage over women in terms of their levels of passion, drive and competitiveness,” the Republican senators said.