What You Need to Know About Two Major Anti-Trans Reports Debunked by Leading Medical Experts

Scientific community rejects U.K.'s Cass Review and Trump's HHS report, but both continue shaping harmful policies

Published: May 14, 2025 | Last Updated: May 14, 2025

Two controversial reports targeting transgender youth health care have been thoroughly rejected by the world's leading medical organizations, yet continue influencing laws that restrict care for millions of young people. Here's what you need to know.

The Cass Review: U.K.'s controversial anti-trans report

Published in April 2024, the Cass Review was commissioned by NHS England to examine gender identity services for children and young people. Dr. Hilary Cass, a pediatrician without clinical or research experience treating trans patients, led the review over four years.

The 388-page report made sweeping recommendations including severely restricting puberty blockers for trans youth under 18, promoting psychotherapy as the primary treatment approach and questioning established practices in transgender health care. The review claimed insufficient evidence exists for current treatment approaches while promoting what critics call "exploratory therapy" — widely recognized as a form of conversion therapy.

Following the report's release, NHS England immediately implemented a ban on puberty blockers for trans youth, though these medications remain available to cisgender children for conditions like precocious puberty. The review has been cited in courts and legislatures worldwide despite facing rejection from major medical organizations.

Trump administration's HHS report

Released earlier this month, this 400-page report emerged from President Trump's executive order titled "Protecting Children from Chemical and Surgical Mutilation." The order gave the United States Department of Health and Human Services just 90 days to produce the review, which health experts say is insufficient time for thorough scientific analysis.

The anonymous authors — HHS refuses to identify them — assert that evidence doesn't support gender-affirming medical interventions for youth. The report promotes discredited theories including "social contagion" and "rapid-onset gender dysphoria" as explanations for increasing numbers of trans-identifying youth. It also suggests autism causes gender dysphoria and classifies social transition (using preferred names and pronouns) as a medical intervention requiring regulation.

The report dismisses decades of research showing benefits of gender-affirming care while claiming these treatments cause significant harm — despite acknowledging only "sparse" evidence for such claims. It promotes "Gender Exploratory Therapy" psychotherapy as the sole appropriate treatment, which medical experts recognize as conversion therapy by another name.

Major medical groups have rejected both reports

Leading health organizations worldwide immediately condemned both documents for misrepresenting established medical consensus:

• World Professional Association for Transgender Health (WPATH)

• American Academy of Pediatrics

• The Endocrine Society

• Association of the Scientific Medical Societies in Germany

• Royal Australian and New Zealand College of Psychiatrists

The American Academy of Pediatrics stated the HHS report "misrepresents the current medical consensus and fails to reflect the realities of pediatric care."

Scientists have identified critical flaws

Independent researchers have documented serious methodological problems in both reports:

Cass review flaws (from the BMC Medical Research Methodology study):

Methodological flaws (excluded trans people and specialists from the review process)
Unsubstantiated claims (asserted treatments ineffective despite contrary evidence)
Unexplained protocol deviations (failed to follow its own stated evidence evaluation methods)
High risk of bias in all seven aspects examined (held gender-affirming care to higher standards than other treatments)

HHS report problems:

Promotes debunked "social contagion" theory (cites 2018 study rejected by medical organizations)
Claims autism causes gender dysphoria without evidence
Dismisses studies showing treatment benefits (ignores peer-reviewed research on improved mental health)
Alleges harm from treatments despite finding "sparse" evidence
Authors remain anonymous, undermining scientific credibility

Both reports share troubling patterns

Exclude input from trans people and their doctors
Promote debunked theories about trans identity
Recommend approaches medical experts call conversion therapy
Hold gender-affirming care to different standards than other treatments
Make claims unsupported by their own evidence

They're still influencing policy

The Cass Review led directly to the U.K.'s ban on puberty blockers for trans youth
Supreme Court Justice Samuel Alito cited the Cass Review in the Tennessee trans health care case
More than half of U.S. states now restrict care for trans minors, often citing the Cass reports, and we can expect the HHS report to be used similarly
Meanwhile, cisgender children can still access puberty blockers for conditions like precocious puberty, leading to questions about the claim that puberty blockers lead to lifetime harms

The bottom line

Two reports with serious scientific flaws and predetermined conclusions are being used to justify sweeping restrictions on trans youth health care — even as the global medical community continues to sound the alarm about their fundamental problems.