The Supreme Court hears arguments on Wednesday in Skrmetti v. U.S., a case of such immense importance to constitutional equality and with such devastating potential consequences that it’s hard to even describe. First and foremost, Skrmetti asks whether legislation that prohibits gender-affirming care for transgender youth is lawful under the 14th Amendment’s equal protection clause. These bans, now enacted in about half the states, have uprooted families across the country, forcing some to travel hundreds of miles, or move to another state, just to maintain their child’s medical treatment. Like abortion restrictions, they represent an abnormal and alarming intrusion into the practice of medicine based on politicians’ personal beliefs about who should be trusted to make decisions about their own bodies.

But Skrmetti is not just about transgender people. It is also, fundamentally, a case about gender equality, and whether constitutional limitations on sex discrimination can survive the Supreme Court’s conservative supermajority. The key legal question in the case is surprisingly easy: Do laws that deny certain medicine to people based exclusively on their sex trigger heightened scrutiny by the courts? The answer, according to long-established precedent, is a resounding yes. If the court decides otherwise, it will shred the constitutional presumption against sex discrimination and replace it with a rubber stamp for states that want to impose their own prejudiced conception of gender roles by force of law. Transgender Americans are, of course, most immediately affected by Skrmetti—but the case really implicates all of our rights. Everyone’s freedom to reject gender stereotypes without fear of state oppression is at stake.

The law at issue in Skrmetti is a Tennessee statute known as S.B. 1, which forbids doctors from providing puberty blockers and hormone therapy to transgender youth. Tennessee is one of nearly 25 states that have enacted such a ban since 2021, when anti-LGBTQ+ activists joined forces with the Republican Party to push these prohibitions nationwide. Every major medical association in the United States, including the American Medical Association and the American Academy of Pediatrics, opposes these laws. These groups agree with expert practitioners who maintain that the benefits of treatment vastly outweigh the risks, and that treatment can in fact be lifesaving for children with gender dysphoria. Bans on this care can have a devastating impact on patients’ health: Laws like S.B. 1 cut off access to medications that resolve minors’ gender dysphoria, forcibly detransitioning them and singling them out as second-class citizens undeserving of medical care that nontrans minors can still freely obtain.

And that is the key point here: S.B. 1, like other trans health bans, does not outlaw gender-related care for everyone. Rather, it targets transgender youth for disfavored treatment, while allowing cisgender peers to get the same medicine. So, for instance, a transgender boy may not under the law undergo testosterone therapy to bring about male puberty, for the sole reason that he is trans. But a cisgender boy can get testosterone therapy—and many do, often to facilitate the development of secondary sex characteristics that affirm their gender identity as male. Hormone treatment for these cisgender kids remains lawful; the exact same treatment for trans kids is banned. The law therefore turns entirely on sex: Children assigned female at birth can’t access specific treatments that are available to children assigned male at birth. Through S.B. 1, Tennessee is promoting its own conception of how young people should fulfill their gender roles. And it isn’t hiding this fact. The statute itself declares that the state’s goal is “encouraging minors to appreciate their sex”—specifically, the sex, and accompanying stereotypes, that Tennessee politicians think a child must adhere to.

This is undisguised sex discrimination. And in a line of precedents stretching back more than 50 years, the Supreme Court has severely curtailed the government’s ability to impose classifications on the basis of sex. The court has held that these laws require an “exceedingly persuasive justification” to survive judicial review. Yet in Skrmetti, the lower court did not apply such heightened scrutiny to S.B. 1. Instead, it deployed mere rational basis review, a far less demanding test that compels great deference to legislative judgments. Judge Jeffrey Sutton’s opinion for the 6th U.S. Circuit Court of Appeals bizarrely insisted that the bill’s classifications are not actually based on sex, all but guaranteeing that the law will survive.

To reach this conclusion, Sutton invoked two principles that would, if embraced by the Supreme Court, fatally undermine the law of sex discrimination. First, he invoked what’s known as the equal-application exception, arguing that S.B. 1 does not differentiate on the basis of sex because both boys and girls are denied cross-sex hormones. Second, he created a new “biological difference” exception to the rule, asserting that Tennessee targeted treatments that, “by biological necessity,” only “one sex can undergo.” According to this logic, since “only females can use testosterone as a transition treatment,” and “only males can use estrogen as a transition treatment,” the state was distinguishing between inherent differences among the sexes, not discriminating on the basis of sex in an effort to enforce “invidious stereotypes.”

Neither of these exceptions is rooted in the law. If they were, the rule against sex discrimination would be toothless. Sutton’s equal-application principle borrows an idea from the days of Jim Crow, when segregationists claimed that race laws—like the ban on interracial marriage—were not discriminatory because they treated the races equally: White people couldn’t marry Black people, and Black people couldn’t marry white people. The Supreme Court rejected this sophistry, holding that any classifications on the basis of race are subject to heightened scrutiny. And it has rejected this theory when applied to men and women as well, ruling that any classification on the basis of sex triggers heightened scrutiny, even if it theoretically affects men and women equally.

Similarly, Sutton’s “biological differences” loophole crashes into contradictory precedent. SCOTUS has held that discrimination purportedly rooted in biological differences cannot escape heightened scrutiny. So, for instance, the Virginia Military Institute’s exclusion of women could not stand despite acknowledged “physical differences” between the sexes, because it impermissibly constrained “educational opportunity” for female applicants. Similarly, the government cannot make it easier for unwed mothers to pass on U.S. citizenship to a child born abroad than it is for unwed fathers; that a mother, unlike a father, gave birth to the child cannot justify the disparate treatment between sexes.

These examples are just a handful of precedents that contradict Sutton’s claims. There are a lot more, to the point that embracing Sutton’s exceptions could gut this whole area of law. Chase Strangio, the ACLU attorney arguing on behalf of the private plaintiffs in Skrmetti, recently explained to Dahlia Lithwick on Amicus that the very premise of constitutional gender equality is at risk. Let S.B. 1 skate with mere rational basis review, and the floodgates are open to a whole new world of state-sanctioned gender-based bias. It would, no doubt, mark open season on transgender people, including adults, who could be subject to the same health bans as minors. (Some states are already restricting their access to gender-affirming care.) But a Supreme Court decision accepting Sutton’s reasoning in Skrmetti would go much further, potentially allowing states to denigrate the rights of men and women because of their sex, either using the smoke screen of some “inherent” biological distinction or avowing that both genders are equally burdened.

Might SCOTUS avoid going down that path? There’s reason for cautious optimism. Both Chief Justice John Roberts and Justice Neil Gorsuch previously upheld protections for transgender people in a federal statute prohibiting sex discrimination, rejecting some of the arguments that Sutton embraced. Both justices, though, could interpret the Constitution differently from a law enacted by Congress. Gorsuch joined Dobbs v. Jackson, whose language Sutton co-opted to subordinate gender equality. He also voted on the shadow docket to reinstate much of Idaho’s trans health ban, though for partly procedural reasons. Perhaps these justices will reaffirm basic sex-discrimination principles that compel heightened scrutiny here. They might then feel obligated to accept the fact that states have no “exceedingly persuasive justification” to outlaw transgender minors’ access to hormone therapies that are endorsed by all major medical associations, and regularly given to cisgender children.

Or the conservative supermajority could, like Sutton, rehash language from Dobbs about deference to democracy and hide behind “judicial restraint” to greenlight these bans. It would be hard to believe that the same justices who have aggressively intervened in democratically enacted gun policy—and securities regulation, and nondiscrimination law, and student loan relief, and affirmative action, and campaign finance, and so much more—have suddenly rediscovered an abiding love for leaving controversial decisions to the people and their representatives. There is, no doubt, a time and place for judges to step back and let these debates play out in the political arena. But openly discriminatory sex-based restrictions on personal freedom are pretty much a textbook example of when courts are constitutionally obliged to step in. If this court refuses to act accordingly, it cannot be trusted with any of our rights.