Archived: The U.K.’s Cass Review Badly Fails Trans Children

A politicized review into transgender medicine in the National Health Service has upended lives in the U.K.—and threatens to spread harm across the globe

In the past decade, an escalating moral panic over transgender people’s existence has embroiled both the U.K. and the U.S. Fear over the experience of children in particular has been stoked by years of provocative media coverage and political posturing. Common disinformation includes baseless claims that trans children are the victims of a “psychic epidemic” or “social contagion,” that they’re being “transitioned” against their will or that they are rushed through medical procedures.

Amid campaigns to roll back legal protections and health care provision for trans people in 2020, the U.K.’s National Health Service (NHS) launched the Cass Review of publicly funded gender services for children in England. Led by retired pediatrician Hilary Cass, the review examined existing research on trans health care interventions for people under age 18, consulted with stakeholders and made recommendations for NHS England services.

The final Cass Review report was released in April. It expresses concern about the number of young trans people presenting at doctors’ offices for treatment and argues there is “remarkably weak evidence” for the benefits of gender-affirming medical interventions. It recommends, for instance, that puberty blockers—medications given to delay puberty—be provided only within a clinical trial. For younger children not yet facing puberty, it raises warnings about social transition—that is, nonmedical decisions kids may make for themselves such as changing their name, wearing different clothes or choosing to be referred to by a different pronoun.

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While the Cass Review has been presented by the U.K. media, politicians and some prominent doctors as a triumph of objective inquiry, its most controversial recommendations are based on prejudice rather than evidence. Instead of helping young people, the review has caused enormous harm to children and their families, to democratic discourse and to wider principles of scientific endeavour. There is an urgent need to critically examine the actual context and findings of the report.

Since its 2020 inception, the Cass Review’s anti-trans credentials have been clear. It explicitly excluded trans people from key roles in research, analysis and oversight of the project, while sidelining most practitioners with experience in trans health care. The project centered and sympathized with anti-trans voices, including professionals who deny the very existence of trans children. Former U.K. minister for women and equalities Kemi Badenoch, who has a history of hostility toward trans people even though her role was to promote equality within the government, boasted that the Cass Review was only possible because of her active involvement.

The methodology underpinning the Cass Review has been extensively criticized by medical experts and academics from a range of disciplines. Criticism has focused especially on the effect of bias on the Cass approach, double standards in the interpretation of data, substandard scientific rigor, methodological flaws and a failure to properly substantiate claims. For example, although the existing literature reports a wide range of important benefits of social transition and no credible evidence of harm, the Cass Review cautions against it. The review also dismisses substantial documented benefits of adolescent medical transition as underevidenced while highlighting risks based on evidence of significantly worse quality. A warning about impaired brain maturation, for instance, cites a single, very short speculative paper that in turn rests on one experimental study with female mice. Meanwhile extensive qualitative data and clinical consensus are almost entirely ignored. These issues help explain why the Cass recommendations differ from previous academic reviews and expert guidance from major medical organisations such as the World Professional Association for Transgender Health (WPATH) and the American Academy of Pediatrics.

WPATH’s experts themselves highlight the Cass report’s “selective and inconsistent use of evidence,” with recommendations that “often do not follow from the data presented in the systematic reviews.” Leading specialists in transgender medical care from the U.S. and Australia emphasize that “the Review obscures key findings, misrepresents its own data, and is rife with misapplications of the scientific method.” For instance, the Cass report warns that an “exponential change in referrals” to England’s child and adolescent gender clinic during the 2010s is “very much faster than would be expected.” But this increase has not been exponential, and the maximum 5,000 referrals it notes in 2021 represents a very small proportion of the 44,000 trans adolescents in the U.K. estimated from 2021 census data.

The Cass report received rapturous support from all sectors of the U.K. media and swift endorsement from the two biggest U.K. political parties, the Conservatives and Labour. It was celebrated as proof that trans rights had indeed “gone too far,” validating years of hateful propaganda. Many politicians and commentators eschewed any mention of the dangers and harms built into Cass’s recommendations. These harms are already being acutely felt by trans children and adolescents around the U.K. and beyond. The Endocrine Society warned that “misinformation about gender-affirming care is being politicized.”

Young trans people across the U.K. now face a plethora of abuses and humiliations promoted and legitimized by the Cass Review. Families, schools and social services have been cautioned against supporting social transition, advice that will keep trans children in situations of prolonged rejection and shame. Newly established gender services in England are not allowed to offer affirming care, instead focusing on invasive and exhaustive assessment. Being trans is regarded as an inherent problem, not a legitimate human identity.

There is currently no pathway to begin NHS medical transition for those under age 18 in the U.K. Puberty blockers are available only hypothetically, through a proposed clinical trial that has not even been designed, much less launched. Whether this unethical trial actually happens is beside the point—it is a tool for the NHS and the U.K. government to deflect accusations of a ban on adolescent health care.

In May the outgoing Conservative government exercised rarely used emergency powers to criminalize possession of puberty blockers sourced privately from outside the NHS. Following the Labour party’s victory in the subsequent general election, new health minister Wes Streeting stated his support for the ban, citing the Cass Review. Criminalization only applies to trans youth: cisgender children and adolescents can still legally access puberty blockers for the same purpose—pausing puberty—and the same medicines continue to be prescribed for a broad range of other conditions and uses.

We estimate more than 1,000 trans adolescents in the U.K. now find that their treatment is illegal. Families risk an up to two-year prison sentence for supporting a child’s continued access to private medication. These adolescents face a state-mandated medical detransition, forcing them to go through a puberty they have fought hard to avoid. The alternative is to flee the country or take greater risks: continue blockers under threat of prosecution or receive alternative medication with more frequent and severe side effects. Families are telling us that fear is driving trans children to discontinue routine hormone monitoring checks and to disengage with wider health care services.

Trans young people have for many years been under severe stress in the U.K. and worldwide, facing growing hostility, persecution and violence. Trans communities and supportive families are now desperately seeking to highlight current threats to young trans people’s safety. In July a group of trans teenagers staged a dramatic four-day sit-in at NHS England headquarters, protesting under the slogan “trans kids deserve better.” The systemic power imbalance that leaves trans youth vulnerable in the U.K. was yet again demonstrated when the U.K. media mostly ignored this unprecedented action.

Trans children now need louder allies from across the wider public, as well as the academic, medical and political establishments. We must clearly call out the gross failures of the Cass Review, acknowledge the violent harms it has already enabled and work proactively to defend all children’s access to prejudice-free health care.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.