This week, the Department of Justice (DOJ) filed a “Statement of Interest” in support of female athletes suing the Connecticut Interscholastic Athletic Conference (CIAC) over its transgender policy. CIAC has claimed that federal law requires schools to allow biological males to compete in women’s sports, while the female athletes claim this constitutes unfair discrimination in violation of Title IX of the Civil Rights Act. The DOJ statement clarifies that federal law does not require or support the CIAC policy.

“Allowing biological males to compete in all-female sports deprives women of the opportunity to participate fully and fairly in sports and is fundamentally unfair to female athletes,” Attorney General William Barr said in a statement Tuesday. “Sports are an important part of education and character development and provide an arena where individual discipline can result in achievement and recognition. The purpose of all-female athletics is to ensure that women have an equal opportunity to participate, compete and excel in this important part of life.”

“Title IX has been a major step forward in the long fight to achieve this equality. As reflected in Title IX, the basis for single-sex athletics, is rooted in the reality of biological differences between the sexes,” Barr argued. “Clearly then, eligibility to participate on a single-sex team must be based on objective biological fact. Girls should not be forced, through the dismantling of Title IX, to be sidelined in their own sports.”

Three female high school athletes filed the lawsuit in February. Among them is Chelsea Mitchell, the fastest biological girl in Connecticut, who nonetheless lost four state championships to male competitors who identify as female. “It’s very unfair for me and the other girls to race against biological males. It has inspired me and the other girls to stand up and fight for our right to compete and to have a fair competition,” Mitchell told PJ Media. “Every race I’ve ever run against the biological males, I’ve lost. It’s definitely very defeating.”

The lawsuit explains that “male puberty quickly increases the levels of circulating testosterone in healthy teen and adult males to levels ten to twenty times higher than the levels that occur in healthy adult females, and this natural flood of testosterone drives a wide range of physiological changes that give males a powerful physiological athletic advantage over females. Inescapable biological facts of the human species [are] not stereotypes, ‘social constructs,’ or relicts of past discrimination.”

The suit lists 8 broad physiological athletic advantages males enjoy over girls and women after the onset of puberty, including larger lungs, larger hearts, an increased number of muscle fibers and muscle mass, higher myoglobin within muscle fibers (enabling faster transfer of oxygen to those muscles), larger and longer bones, increased mineral density in bones, and height. Due to these advantages, sporting events have long had different standards for girls and boys. Even the pro-transgender Journal of Medical Ethics has condemned the “intolerable unfairness” of the Olympic Committee’s pro-transgender rules.

Yet CIAC claims its hands are tied on the issue, arguing that “federal law” requires this unfair state of affairs. Under former President Barack Obama, the DOJ interpreted Title IX’s prohibition of discrimination on the basis of sex to apply to transgender identity. Under Trump, the DOJ has reversed this stance, arguing in a Supreme Court case that the authors of Title IX could not have meant to include transgender identity in the meaning of “sex.” The Trump DOJ did not join the Connecticut high school girls’ lawsuit, but it did file a “Statement of Interest” to make it clear that the CIAC is wrong about federal law.

“They are incorrect,” the statement of interest argues. “Title IX and its implementing regulations prohibit discrimination solely ‘on the basis of sex,’ not on the basis of transgender status, and therefore neither require nor authorize CIAC’s transgender policy. To the contrary, CIAC’s construction of Title IX as requiring the participation of students on athletic teams that reflect their gender identity would turn the statute on its head.”

“One of Title IX’s core purposes is to ensure that women have an ‘equal athletic opportunity’ to participate in school athletic programs. … Schools realize that purpose primarily by establishing separate athletic teams for men and women and by ensuring that those teams are on equal footing,” the statement argues. Far from being required by Title IX, CIAC’s transgender policy is in tension with ‘the core of Title IX’s purpose.'”

Gender dysphoria — the persistent and painful sense of identifying with the gender opposite one’s biological sex — is real, but it does not change biological reality. Even experimental “treatments” like cross-sex hormones and transgender surgery cannot alter a person’s DNA and development — even in the womb, males and females develop differently. The DOJ is right to champion the biological and plain meaning of the term “sex” against transgender activism.

Follow Tyler O’Neil, the author of this article, on Twitter at @Tyler2ONeil.