The disagreement boiled down to a perennial question in constitutional cases: How much overinclusion or underinclusion in a law is acceptable? Nobody in this case was challenging the practice of separating sports teams into male and female categories. The division of people into these two groups for athletic purposes is accepted as, roughly, good enough, even though some male and female individuals have inborn physical attributes that make them outliers for their sex. And people don’t generally find it unfair that Michael Phelps’s extraordinary wing span, or Serena Williams’s unusual muscle mass, provides an advantage over competitors. The Court understood a state’s decision to divide sports into “biological male” and “biological female” teams as similarly good enough to satisfy intermediate scrutiny. “Not every biological male athlete is bigger, stronger, faster, or otherwise more athletically able than every biological female athlete,” Kavanaugh wrote. The fact that some transgender girls may, through gender-affirming medical treatment, eliminate the athletic advantages typical of biological males and have athletic capabilities typical of biological females did not, in the Court’s view, make it unconstitutional to exclude all transgender girls from girls’ teams.
Kavanaugh described the alternative world—the one the dissenters were after—in which a court’s conclusion must depend on whether a particular transgender girl actually poses a risk to safety and competitive fairness, as a “judicial quagmire.” “Individuals come in all shapes and sizes, with different height, weight, muscle mass, heart capacity, lung capacity, strength, speed, endurance, jumping ability, and so on,” he wrote. Kavanaugh balked at the prospect of courts “determining the effects of the puberty blockers and hormones taken by transgender athletes—and then comparing each of those transgender athletes’ abilities to those of other individual biological males and individual biological females in the relevant sport.” He said it would be “almost impossible” for a judge to do it equitably. It is, however, the kind of complicated factual inquiry that trial courts are routinely asked to undertake.
Courts also commonly sort through medical science presented by opposing sides. In this case, neither side could confidently trumpet the science, even though their arguments circled around it. Last year, in United States v. Skrmetti, the Court declined to invalidate a state ban on the use of puberty blockers and hormones to treat minors’ gender dysphoria, in part because it didn’t wish to “second-guess” the legislature’s decision in the face of medical uncertainty on the long-term outcomes of those treatments. The medical science regarding the effect of gender-affirming treatments on athletic advantage is unsettled; the International Olympic Committee stated, in March, that “there is no current evidence that testosterone suppression or gender-affirming hormone treatment eliminates this advantage.” Following Skrmetti’s lead in the face of uncertain science on the question, the Court declined to find that states were wrong to believe that “at least some biological males who have taken puberty blockers or hormones still retain physical advantages over females.”
Kavanaugh’s opinion left the strong impression of a Justice who has skin in the game, so to speak. It is well known that Kavanaugh has been a coach of his daughters’ youth-sports teams. His paean to female athletics read like a proud sports dad speaking up for his daughters—or a cross between a Nike ad and a tampon commercial: “They spend extraordinary time and effort to train in the heat and in the cold, to work out early in the morning and late at night, to get a little faster, to become a little stronger, to jump a little higher, to shoot a little better, to watch a little more video, to make the lonely journey back from an A.C.L. tear, to scrap for playing time, to start, to win the game, to win a championship, to hang a banner, to bring home a medal, to be all-tournament, all-county, all-State, or all-American. They put a championship trophy or all-league award on their bedroom shelf—and it stays there forever as a reminder of their love of the game and pride in their achievements.”
Kavanaugh emphasized that “sports are generally zero sum”—meaning that an athlete who makes a team, gets playing time, wins a match, or earns an athletic scholarship “deprives another athlete” of that opportunity. There are winners and losers. Justice Kavanaugh’s heart bleeds for girls participating in “the human drama of athletic competition, to overcome the agony of defeat and know the thrill of victory.” He seems to have a clear sense that a loss for transgender girls in this case is a win for other girls. And, as if to model the lesson of sportsmanship, he made a point of stating that “we greatly admire the desire of all students, including transgender students, such as B.P.J., who want to participate in sports.” As if to display the opposite, Justice Clarence Thomas wrote in a concurrence that “Men and boys with gender dysphoria are not women or girls, even if they believe that they are.”
