Amicus Brief: United States v. Skrmetti

Tennessee’s Senate Bill 1 prohibits medical procedures intended to conform a minor’s appearance to an identity inconsistent with the minor’s biological sex. About half the states in the nation have similar laws. The federal government claims that denying two medical interventions—so-called “puberty blockers” and cross-sex hormones—to minors with gender dysphoria constitutes sex and transgender-status discrimination. It argues that this violates the Fourteenth Amendment’s Equal Protection Clause because SB 1 denies to minors who identify as transgender treatments they could receive for reasons other than gender dysphoria. The Sixth Circuit ruled in Tennessee’s favor, so the federal government took the case to the Supreme Court.

The Manhattan Institute, building on the work of Dr. Leor Sapir, has filed a brief to relate that well-established scientific evidence and a growing international consensus among medical professionals and authorities advise against the use of “gender-affirming” medications as first-line treatments for pediatric gender dysphoria. The most comprehensive assessment of the risks and benefits of pediatric gender medicine to date, conducted in the U.K. by Dr. Hilary Cass and finalized in April 2024, found “remarkably weak” evidence for the safety and efficacy of such medications. The Cass Review calls for a cautious, individualized approach to gender dysphoria that prioritizes psychotherapy. Medical organizations in the United States, however, have largely diverged from this cautious international approach, favoring aggressive “gender affirming” treatments.

Case in point: The brief by Dr. Meredithe McNamara and other researchers supporting the federal government casts doubt on the validity and ethical appropriateness of the Cass Review. Given the influence and prestigious positions that McNamara and her colleagues possess within the world of gender medicine and as expert witnesses in ongoing lawsuits, it is essential that the Supreme Court recognize and understand the flaws and misrepresentations in their arguments.

First, McNamara et al. conflate the overall quality of evidence with the quality of individual studies. According to the GRADE system—a widely accepted framework in evidence-based medicine—“quality of evidence” reflects the degree of confidence that the estimate of effect of an intervention reflects the true effect. “Quality of individual studies,” by contrast, indicates the risk of bias, such as when confounding factors can explain the observed outcome.

In not differentiating between these concepts, McNamara et al. set the reader up for a second fallacy, when it misrepresents the evidence from individual studies. McNamara et al. cite specific studies as "robust" and "reliable," yet these studies suffer from serious methodological flaws. The studies’ findings were mischaracterized by their own authors, who are gender clinicians with significant conflicts of interest. In one of the studies, two adolescents committed suicide after receiving “gender-affirming” treatments.

Third, McNamara et al. argue that requiring higher-quality evidence for gender-affirming interventions imposes an unrealistic burden compared to other areas of pediatric medicine. They warn that failure to rule in favor of petitioner would “create chaos in the day-to-day practice of pediatrics.” But this claim is fearmongering, and the proof of this are the very examples they offer of other “low quality” evidence treatments. As we show, implicit in the McNamara brief’s warning about “chaos in the field” is an assumption about suicide risk that numerous health authorities now reject.

Finally, the significant discrepancies among the McNamara group, the American Academy of Pediatrics, and other U.S. medical organizations reveal a lack of consensus on core issues related to adolescent gender-affirming care. Disagreement over such questions as whether puberty blockers are diagnostic underscores the enduring confusions in the field.

Given these profound uncertainties and the untrustworthiness of clinicians who practice and claim special expertise in youth gender medicine, states like Tennessee are justified in taking steps to protect minors from potentially harmful medical interventions that are not supported by rigorous, reliable evidence.

Leor Sapir is a fellow at the Manhattan Institute.

John Ketcham is a legal policy fellow and director of Cities Policy at the Manhattan Institute.

Ilya Shapiro is a senior fellow and director of Constitutional Studies at the Manhattan Institute. Follow him on Twitter here.

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