Why Male Athletes Who Identify as Transgender Should Not Compete in Women’s Sports

Ask most people whether a boy should compete on a girls’ team, and the answer is obvious: of course not. Boys have inherent biological advantages in sports, and pitting them against female athletes in competition would be unfair.

Yet, despite the vast majority of Americans agreeing that boys shouldn’t compete in girls sports, girls across the country are being asked to accept exactly that—and a generation of female athletes is paying for it.

Adaleia Cross is one of them.

Real Women. Real Harm.

Adaleia Cross loved track and field. She trained hard, competed harder, and had earned her spot at a championship meet. Then, a male student joined the girls’ team and took it from her.

But that was just the beginning. The same male athlete would go on to sexually harass Adaleia in the locker room. It got so bad that she eventually left the sport she loved. In the years since, this one male athlete has defeated more than 470 girls pushing them down the ranking a combined 1,400 times.

The harm isn’t hypothetical. It’s actually playing out in gyms, on tracks, in pools, and in locker rooms across the country. Male athletes who identify as female are competing in women’s sports at every level—high school, collegiate, and professional—and winning.

Lia Thomas, a male swimmer who spent three years competing on the men’s team at the University of Pennsylvania, went from 65th in men’s national rankings to first in women’s after switching to the women’s team, ultimately winning the 2022 NCAA women’s championship in the 500-yard freestyle and beating two former female Olympic medalists in the process. Thomas is far from alone. As a U.N. report documented, male athletes have broken records and taken titles from women across at least 29 different sports—swimming, track, powerlifting, cycling, golf, and more. These examples speak for themselves.

This issue extends far beyond the scoreboard. When we can no longer define what a woman is, the very notion of female privacy is also at risk: in locker rooms, restrooms, homeless shelters, prisons, and on school trips. What happens on the field is just the beginning.

Those who simply state these facts are often met with ridicule. But the science, the scoreboards, and the stories of girls like Adaleia don’t bend to ideology. Men and women are genuinely, meaningfully different—and that difference isn’t some problem to be “solved.” It’s a reality that women’s sports exist to honor.

And thankfully, the Supreme Court’s landmark decision in two ADF cases allows states to affirm exactly that.

Is it fair for males to compete in women’s sports? Here’s the science.

Some argue that males who lower their testosterone with cross-sex hormones should be allowed to compete against females. But the science doesn’t support that. An expert report by Dr. Gregory Brown, an exercise science professor at the University of Nebraska, makes three things clear.

1. In nearly every sport, men outperform women. Similarly gifted and trained males have built-in physical advantages—longer and stronger bones, larger muscles, lower body fat. The gaps are measurable: men have 60 to 100 percent greater arm strength, run 10 to 13 percent faster, and 15 to 24 percent greater jump performance. They throw a baseball 35 percent faster and spike a volleyball 29 to 34 percent faster. These are not opinions. They are biological facts.
2. Male advantages exist even before puberty. It’s tempting to assume these advantages arrive only with male puberty. They don’t. A European study of more than 10,000 elementary-age children found that between ages 6 and 10, boys outperformed girls at every age in grip strength, jumping, and aerobic capacity. One study found boys aged 3.5 to 4.5 were consistently stronger despite no difference in muscle size—evidence the gap is rooted in biology, not training. Puberty widens the gap; it doesn’t create it.
3. Testosterone suppression doesn’t erase the advantage. Many associations have tried to level the field by requiring males to suppress their testosterone. It doesn’t work. One study found males lost only about 7 percent of their grip strength after a year, leaving most of a roughly 60 percent advantage intact. A study of running speed found males ran 21 percent faster than the female average before suppression and still ran 12 percent faster two years later. As Dr. Brown notes, very few male advantages that develop during puberty can be reversed afterward—and suppression does nothing for advantages in skeletal structure, heart and lung capacity, and muscle mass.

The conclusion is hard to escape. Whether at the elite, collegiate, or scholastic level, males retain a competitive edge over similarly gifted, aged, and trained females—and protecting fair competition for women and girls means keeping the female category female.

Title IX and the fight to protect women’s sports

In today’s world, it’s difficult to imagine that there was a time when women and girls didn’t have many opportunities to play sports.

But before the 1970s, the concept of women’s sports was not widespread at all. In fact, sporting events for girls were almost nonexistent. During the 1971-1972 school year, only 7 percent of high school athletes were girls. In the 2018-2019 school year, by comparison, girls made up over 42 percent of all high school athletes.

So, what changed? In 1972, Congress passed Title IX— legislation intended to give women and girls equal opportunity in education. In the decades since, it has opened the door for women and girls to compete in athletics. Title IX changed the game.

But in recent years, men have been increasingly allowed to compete in women’s sports, undermining the very purpose of Title IX itself. In response, more than half of states have passed laws to protect women’s sports, including Idaho and West Virginia.

• In Idaho, Madison Kenyon and Mary Kate Marshall, two collegiate athletes at Idaho State University, spent years training to be the best that they could be. However, in 2019, the two learned that they would be competing against a male athlete who had spent the prior three years posting times faster than the women’s national records. Both Madison and Mary Kate lost. Idaho responded in March 2020 by becoming the first state in the country to pass a law—the Fairness in Women’s Sports Act—ensuring that only female athletes could compete in sports designated for women and girls. ADF helped craft that law. Weeks later, the American Civil Liberties Union (ACLU) filed suit to strike it down. Madison and Mary Kate intervened to help defend it.
• In West Virginia, a similar story has played out. Lainey Armistead dedicated her life to soccer—competing at the collegiate level and serving as team captain at West Virginia State University. When West Virginia passed its own Save Women’s Sports Act in 2021, she was elated. When the ACLU sued again, Lainey knew she couldn’t standby and watch a male athlete displace girls from the sport’s competitions in her state. ADF intervened on Lainey’s behalf.

In July 2025, the Supreme Court agreed to hear both State of West Virginia v. B.P.J. and Little v. Hecox. Oral arguments were heard on January 13, 2026, with West Virginia Attorney General JB McCuskey and Idaho Attorney General Raúl Labrador leading the charge for their respective states. ADF serves as co-counsel for the states in both cases and also represents the female athletes who intervened to defend these laws from the beginning.

In June 2026, the U.S. Supreme Court gave a sweeping victory for women and girls, upholding West Virginia’s and Idaho’s women’s sports laws that ensure that males cannot compete in women’s sports.

The Court wrote in the majority opinion, “The two States here—along with 25 other States, the IOC, the USOPC, and the NCAA—have concluded at this time that women and girls should be allowed to compete for those life-changing opportunities on an equal playing field, without fear of physical injury from biological males or being forced to compete against biological males. Consistent with Title IX and the Equal Protection Clause, we hold that the States may maintain women’s and girls’ sports for biological females. They may determine eligibility for women’s and girls’ sports based on biological sex. The Constitution and Title IX do not require an overhaul of women’s and girls’ sports throughout America.”

As the decision mentioned, 27 states have now passed laws ensuring fairness in women’s sports. But 23 have not. West Virginia AG JB McCuskey and Idaho AG Raúl Labrador showed what leadership looks like. Every lawmaker and school administrator in the remaining 23 states should act to protect women’s sports — or answer for why they didn’t. The girls in these states are watching and waiting.

This issue goes beyond sports

There is a painful human cost to accepting the lie that men can become women, and it goes well beyond sports.

When one cannot define what a woman is—like the ACLU’s legal team is unable to do—every female suffers. There is nothing abstract or theoretical about the harm that women face when the gender ideology lie is accepted as truth. And that harm can take a multitude of forms.

• Girls on school trips are being assigned to share hotel rooms with boys on overnight school trips without notice or their parents’ consent.
• Survivors of sex trafficking and horrific abuse (often at the hands of men) have been told that men must be allowed into homeless shelters—for women.
• Making matters worse, young people like Chloe Cole and Prisha Mosley are being encouraged to harm their bodies in pursuit of a lie. There is simply no reason for a girl to suddenly have her healthy breasts removed, period.
• And worse yet, the lie of gender ideology has also encroached on the very ability of parents, doctors, and counselors to help children in need. In Michigan, Dan and Jennifer Mead only found out that their daughter’s middle school was socially transitioning her because school employees failed to fully alter a document that referred to her by a masculine name and male pronouns. No one notified the Meads or sought their consent before socially transitioning their daughter.
• In Colorado, officials have tried to tell counselors like Kaley Chiles what she could and could not say to her minor clients about gender and sexuality. Thankfully, the Supreme Court overwhelmingly ruled in Kaley’s favor, protecting her freedom of speech.

Everyone should already know that male athletes are generally bigger, faster, and stronger than female athletes. The more our laws and policies acknowledge the truth about the differences between men and women, the more safety and fairness for female athletes will be protected. When we reject truth, the harm is real, widespread, and devastating.