White Paper Addresses Key Issues in Legal Battles over Gender-Affirming Health Care

transgender flags in a row on grass

Professor Anne Alstott of Yale Law School and Dr. Meredithe McNamara of the Yale School of Medicine, the co-founders of The Integrity Project at Yale Law School, have co-authored a white paper with a team of international scientists that takes an expert, evidence-based approach to discussing key issues at stake in current legal battles to preserve access to health care for transgender youth. 


Legal battles over transgender rights continue nationwide. From 2022 through 2024, 25 U.S. states have enacted legislation that bans gender-affirming health care for transgender youth. Litigation is ongoing in at least 10 states. A number of federal and state trial courts have enjoined these laws either temporarily or permanently, but some of these decisions have been reversed on appeal, with a 2024 Supreme Court ruling narrowing the legal remedies available to challengers of the bans. On June 24, the Supreme Court agreed to hear the federal government’s challenge to Tennessee’s ban on gender-affirming care, with a decision expected next year. 

Central to all these cases is validity of the scientific evidence supporting gender-affirming care. (“Gender-affirming care” refers to the individualized treatments provided by medical professionals to trans youth with gender dysphoria. Treatments can include puberty-pausing medications and gender-affirming hormone therapy.) In prior work, The Integrity Project has reviewed the scientific evidence, which confirms that gender-affirming care is standard health care, well grounded in solid studies and authoritative clinical practice guidelines, and has shown that state bans often rest on scientific misinformation

Critiquing the Cass Review

The new white paper provides an evidence-based critique of a recent independent review in the U.K., known as the “Cass Review,” that has become central to U.S. litigation. The NHS recently cited the Cass Review in announcing its decision to deny puberty-pausing medications to those under age 18 outside of a research setting. In June 2024, the NHS Health Secretary cited the Review as the rationale for emergency regulations that criminalize the supply of puberty-pausing medications to new patients under 18 in England, Scotland, and Wales. 

States and their amici, as well as conservative commentators, have cited these events as support for U.S. bans on gender-affirming care and have characterized the Cass Review as casting doubt on the scientific evidence base for gender-affirming care. Some academics have raised concerns about the Cass Review, but major news outlets have given the Review positive coverage, treating its findings as authoritative. The Cass Review has already been cited by states in preliminary filings with the Supreme Court.

Alstott, McNamara, and their co-authors evaluate the Cass Review and reach a very different conclusion. In fact, the Cass Review does not recommend a ban on gender-affirming medical care, the white paper states. 

“It is vital that the national and international medical community, policymakers, and the media understand what the Cass Review is and what it is not,” Alstott said. “The Review will likely be cited by states attempting to ban gender-affirming care, but, in fact, it is does not recommend a ban on medical care for transgender youth.” 

Although the Cass Review does criticize the evidence base for gender-affirming care, the Review’s conclusions in this regard are unsupported,” according to McNamara.

According to Dr. McNamara, “The Cass Review is an important document for those considering how to remedy the shortage of health services for transgender young people in the U.K. It is not an authoritative guideline or standard of care, nor is it an accurate restatement of the available medical evidence on the treatment of gender dysphoria. 

Troublingly, according to the new white paper, the Cass Review “levies unsupported assertions about gender identity, gender dysphoria, standard practices, and safety of gender-affirming medical treatments, and it repeats claims that have been disproved by sound evidence.” Additionally, the white paper states that the systematic reviews the Cass Review relied on have serious methodological flaws, including the omission of key findings in the extant body of literature.

The new white paper is co-authored by a group of eight legal scholars and scientists. The scientists include M.D. and Ph.D. researchers, academics, and physicians; all have expertise in research and/or clinical practice in gender-affirming care; and their areas of specialty include adolescent medicine, pediatric endocrinology, child and adolescent psychiatry, and epidemiology.

In addition to Alstott and Dr. McNamara, the distinguished authors include Kellan Baker, Ph.D., Executive Director of the Whitman-Walker Institute; Kara Connelly, M.D., Associate Professor of Pediatrics, Division of Endocrinology, School of Medicine, Oregon Health & Science University; Aron Janssen, M.D., Associate Professor of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine; Johanna Olson-Kennedy, M.D., Professor of Clinical Pediatrics, Keck School of Medicine of USC; Ken C Pang, FRACP, Ph.D., NHMRC Leadership Fellow and Senior Principal Research Fellow, Murdoch Children’s Research Institute, VIC Australia; Ayden Scheim, Ph.D., Assistant Professor of Epidemiology, Drexel University Dornsife School of Public Health; Jack Turban, M.D., Assistant Professor, Psychiatry, University of California, San Francisco.