Britain Confronts the Shaky Evidence for Youth Gender Medicine

In a world without partisan politics, the Cass report on youth gender medicine would prompt serious reflection from American trans-rights activists, their supporters in the media, and the doctors and institutions offering hormonal and surgical treatments to minors. At the request of the English National Health Service, the senior pediatrician Hilary Cass has completed the most thorough consideration yet of this field, and her report calmly and carefully demolishes many common activist tropes. Puberty blockers do have side effects, Cass found. The evidence base for widely used treatments is “shaky.” Their safety and effectiveness are not settled science.

The report drew on extensive interviews with doctors, parents, and young people, as well as on a series of new, systematic literature reviews. Its publication marks a decisive turn away from the affirmative model of treatment, in line with similar moves in other European countries. What Cass’s final document finds, largely, is an absence. “The reality is that we have no good evidence on the long-term outcomes of interventions to manage gender-related distress,” Cass writes. We also don’t have strong evidence that social transitioning, such as changing names or pronouns, affects adolescents’ mental-health outcomes (either positively or negatively). We don’t have strong evidence that puberty blockers are merely a pause button, or that their benefits outweigh their downsides, or that they are lifesaving care in the sense that they prevent suicides. We don’t know why the number of children turning up at gender clinics rose so dramatically during the 2010s, or why the demographics of those children changed from a majority of biological males to a majority of biological females. Neither “born that way” nor “it’s all social contagion” captures the complexity of the picture, Cass writes.

What Cass does feel confident in saying is this: When it comes to alleviating gender-related distress, “for the majority of young people, a medical pathway may not be the best way to achieve this.” That conclusion will now inform the creation of new state-provided services in England. These will attempt to consider patients more holistically, acknowledging that their gender distress might be part of a picture that also includes anxiety, autism, obsessive-compulsive disorder, eating disorders, or past trauma.

This is a million miles away from prominent American medical groups’ recommendation to simply affirm an adolescent’s stated gender—and from common practice at American gender clinics. For example, a Reuters investigation found that, of 18 U.S. clinics surveyed, none conducted the lengthy psychological assessments used by Dutch researchers who pioneered the use of medical gender treatments in adolescents; some clinics prescribe puberty blockers or hormones during a patient’s first visit. Under pressure from its members, the American Academy of Pediatrics last year commissioned its own evidence review, which is still in progress. But at the same time, the group restated its 2018 commitment to the medical model.

The Cass report’s findings also contradict the prevailing wisdom at many media outlets, some of which have uncritically repeated advocacy groups’ talking points. In an extreme example recently noted by the writer Jesse Singal, CNN seems to have a verbal formula, repeated across multiple stories, to assure its audience that “gender-affirming care is medically necessary, evidence-based care.” On a variety of platforms, prominent liberal commentators have presented growing concerns about the use of puberty blockers as an ill-informed moral panic.

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The truth is that, although American medical groups have indeed reached a consensus about the benefits of youth gender medicine, doctors with direct experience in the field are divided, particularly outside the United States. “Clinicians who have spent many years working in gender clinics have drawn very different conclusions from their clinical experience about the best way to support young people with gender-related distress,” Cass writes. Her report is a challenge to the latest standards of care from the U.S.-based World Professional Association for Transgender Health, which declined to institute minimum-age limits for surgery. The literature review included with her report is notably brutal about these guidelines, which are highly influential in youth gender medicine in America and around the world—but which, according to Cass, “lack developmental rigour.”

The crux of the report is that the ambitions of youth gender medicine outstripped the evidence—or, as Cass puts it, that doctors at the U.K. clinic whose practices she was examining, although well-meaning, “developed a fundamentally different philosophy and approach compared to other paediatric and mental health services.” How, she asks, did the medical pathway of puberty blockers and then cross-sex hormones—a treatment based on a single Dutch study in the 1990s—spread around the world so quickly and decisively? Why didn’t clinicians seek out more studies to confirm or disprove its safety and utility earlier? And what should child gender services look like now?

The answer to those first two questions is the same. Medicalized gender treatments for minors became wrapped up with a push for wider social acceptance for transgender people, something that was presented as the “next frontier in civil rights,” as Time magazine once described it. Any questions about such care were therefore read as stemming from transphobic hostility, full stop. And when those questions kept coming anyway, right-wing politicians and anti-woke comedians piled on, sensing an area where left-wing intellectuals were out of touch with popular opinion. In turn, that allowed misgivings to be dismissed as “fascism,” even though, as the British journalist Sarah Ditum has written, “it is not damning of feminists that they are on the same page as Vladimir Putin about there being two sexes. That is just how many sexes there are.”

In Britain, multiple clinicians working at the Gender Identity and Development Service (GIDS) at the Tavistock and Portman Trust, the central provider of youth gender medicine, tried to raise their concerns, only to have their fears dismissed as hostility toward trans people. Even those who stayed within the service have spoken about pressure from charities and lobbying groups to push children toward a medical pathway. As Cass notes, “There are few other areas of healthcare where professionals are so afraid to openly discuss their views, where people are vilified on social media, and where name-calling echoes the worst bullying behaviour.”

This hostile climate has hampered attempts to collect robust data about real-world outcomes. The report’s research team at the University of York tried to follow up on 9,000 former GIDS patients but was informed by National Health Service authorities in England in January that “despite efforts to encourage the participation of the NHS gender clinics, the necessary cooperation had not been forthcoming.” Cass has since wondered aloud if this decision was “ideologically driven,” and she recommends that the clinics be “directed to comply” with her team’s request for data.

As I have written before, the intense polarization of the past few years around gender appears to be receding in Britain. Kamran Abbasi, the editor in chief of The BMJ, the country’s foremost medical journal, wrote an editorial praising the report and echoing its conclusion that many “studies in gender medicine fall woefully short in terms of methodological rigour.” The country’s left-wing Labour Party has already accepted that feminist concerns about gender self-identification are legitimate, and its health spokesperson, Wes Streeting, welcomed the Cass report as soon as it was published. (The ruling Conservatives have also enthusiastically embraced its conclusions, and the former health secretary Sajid Javid pushed through a law change that made its data collection possible.)  The LGBTQ charity Stonewall responded to the report by saying that some of its recommendations could be “positive,” and urged politicians to read it. Even Mermaids, the charity most associated with pushing the affirmative model in Britain, offered only lukewarm criticism that more gatekeeping could further increase waiting times.

The Cass report is a model for the treatment of fiercely debated social issues: nuanced, empathetic, evidence-based. It has taken a political debate and returned it to the realm of provable facts. And, unlike American medical groups, its author appears to have made a real effort to listen to people with opposing views, and attempted to reconcile their very different experiences of this topic. “I have spoken to transgender adults who are leading positive and successful lives, and feeling empowered by having made the decision to transition,” she writes in the introduction. “I have spoken to people who have detransitioned, some of whom deeply regret their earlier decisions.” What a difference from America, where detransitioners are routinely dismissed as Republican pawns and where even researchers who are trans themselves get pushback for investigating transition-related regret—and where red states have passed laws restricting care even for transgender adults, or have proposed removing civil-rights protections from them.

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Has the Cass report gotten everything right? The methodology and conclusions of its research should be open to challenge and critique, as with any other study. But it is undoubtedly the work of serious people who have treated a delicate subject seriously. If you still think that concerns about child medical transition are nothing more than a moral panic, then I have a question: What evidence would change your mind?