In sports, you win some and you lose some. Everyone knows and accepts this. But being cheated against is any athlete’s worst nightmare.

It’s a form of theft, taking away years of training in a moment of dishonesty. And when it happened to Mary Kate Marshall, a sprinter for the Idaho State University Bengals, she decided to act.

A competitor in championship races, Marshall was astonished to be placed in a lower racing category after losing a race. It’s not that Marshall is a sore loser—it’s that she lost to a man.

“When I lose to another woman, I assume that she must train harder than I do and it drives me to work harder,” says Marshall. “If I lose to a man, it feels completely different. It’s deflating. I wonder whether he has to work as hard as I do, whether he was even trying, or was that an easy race for him. It makes me think that no matter how hard I try, my hard work and effort will not matter.”

This experience led Marshall and her fellow Tiger Madison Kenyon to file a lawsuit, with the help of the Family Research Council’s friends at the Alliance Defending Freedom, to stop biological men from competing in women’s sporting events. And it also led Idaho state Rep. Barbara Ehardt, R-Idaho Falls, to author the Fairness in Women’s Sports Act.

Ehardt knows something about women’s athletics. For 15 years, she was an NCAA Division I women’s basketball coach, serving at four universities, including a stint as head coach at Cal State-Fullerton. Ehardt was herself a college basketball player who credits sports with helping her achieve her personal and professional goals.

Explaining the reason for her bill, she says that it “would ensure that girls and women are competing on a fair and level playing field against other girls and women.” And it’s not as though males can’t play sports—as the state legislator notes, “boys and men have their opportunities to compete and those will not be taken away.”

The measure, passed overwhelmingly in the Idaho Legislature and signed into law by Gov. Brad Little, a Republican, cites a federal court ruling recognizing that men and women “have inherent differences” and that these differences are a cause for celebration.

The bill also quotes from a Psychology Today article that says usually, men have “denser, stronger bones, tendons, and ligaments” and “larger hearts, greater lung volume per body mass, a higher red blood cell count, and higher hemoglobin.”

In other words, with rare exceptions, men can run longer and faster than can women. So, if women compete against men in athletics, the biological deck is stacked against them.

But as you might expect, the American Civil Liberties Union has gotten into the act and sued.

Not confident in its lawsuit that is heavy on feelings and light on facts, the ACLU is also pressuring the NCAA to remove its 2021 men’s basketball tournament from Idaho’s Boise State University, and the NCAA has said it will consider doing this at a meeting in August. The fact that the ACLU would resort to this tactic shows it knows how weak its legal case is.

In response, Christiana Holcomb of Alliance Defending Freedom writes that it is “profoundly ironic and deeply disappointing” that the NCAA is considering this action.

“Comparably fit and trained male athletes will always have physical advantages over females; that’s the whole reason we have girls’ sports as a separate category,” Holcomb writes.

And as Ehardt said in an interview with the Family Research Council’s Sarah Perry, the NCAA seems to be “turning on women. It’s so disappointing to see this.”

Idaho State runner Madison Kenyon put it eloquently: “Allowing males to enter women’s sports defeats an entire aspect of sports: It eliminates the connection between an athlete’s effort and her success.”

Kenyon raises the key point: It’s really a matter of justice.

“Sex separation in sports,” she says, “helps ensure that males and females each enjoy opportunities for fair competition and victory.”

Originally published in Tony Perkins’ Washington Update, which is written with the aid of Family Research Council senior writers.