Intended for healthcare professionals

Feature BMJ Investigation

Gender medicine in the US: how the Cass review failed to land

BMJ 2024; 385 doi: (Published 23 May 2024) Cite this as: BMJ 2024;385:q1141
  1. Jennifer Block, freelance journalist
  1. writingblock{at}

A landmark investigation with bearing on the future of gender identity services for children and adolescents has been pivotal in the UK—and largely ignored by US medical organisations and media. Jennifer Block reports on how America has resisted the push for a more holistic approach

The newly released Cass review on transgender care for under 18s has had a seismic effect across the United Kingdom and Europe.1 Scotland and Wales promptly followed the NHS in England in ceasing the prescription of puberty “blocking” drugs outside of research protocols. The UN special rapporteur on violence against women and girls, Reem Alsalem, called the independent inquiry’s findings and recommendations “seminal” and stated that policies on gender treatments have “breached fundamental principles” of children’s human rights, with “devastating consequences.” Some charities and clinicians are disappointed with last month’s final review report. But the tone of major print and broadcast media in the UK has shifted: outlets that have previously reported criticism of gender services as transphobic now note how, as the Guardian reported, “the lack of high quality research, highlighted by Cass, has been a subject of growing unease among doctors.”

The review by Hilary Cass, paediatrician and former president of the Royal College of Paediatrics and Child Health, was commissioned by the NHS and built on the findings of Cass’s 2022 interim report. Then, she found that the evidence underpinning the treatment intensive, “gender affirming” model of care for distressed young people was “limited” and “inconclusive.” The final report is even clearer: “The reality is that we have no good evidence on the long term outcomes of interventions to manage gender related distress.”

But in the United States, where the gender affirming model is the norm, the effect of Cass’s four year investigation and final report isn’t yet obvious. “Unfortunately, Cass does not seem to be penetrating the public consciousness,” says Zhenya Abbruzzese, cofounder of the four year old Society for Evidence Based Gender Medicine (SEGM), a group of researchers and clinicians that has pushed for systematic reviews and an evidence based approach.

Cracks in medical consensus

Of the eight systematic reviews that Cass commissioned, two looked at nearly two dozen professional guidelines and found that most lack “developmental rigour.”23 More concerning, Cass exposed how they are built on “circularity,” drawn from years old versions of guidelines issued by the World Professional Association for Transgender Health (WPATH) and the Endocrine Society, each of which refer to the other rather than to high quality evidence. “This approach may explain why there has been an apparent consensus on key areas of practice despite the evidence being poor,” writes Cass. Neither group responded to The BMJ.

The American Academy of Paediatrics (AAP) and the Endocrine Society have stood by their guidelines. The Cass review “does not contain any new research that would contradict” them, the Endocrine Society said in a statement.4 WPATH issued an email statement that Cass “is rooted in the false premise that non-medical alternatives to care will result in less adolescent distress,” and added on 17 May that its own guidelines were “based on far more systematic reviews [than] the Cass review.”5 As The BMJ reported last year,6 WPATH’s own systematic review, one of an unknown number commissioned for the eighth version of its Standards of Care—just two were published—concluded that the strength of the evidence to support the mental health benefits of hormones was “low” and that it was “impossible” to conclude how they affect suicide risk.

Under pressure from some members, the AAP announced last year that it would commission an independent systematic review of the evidence for the affirmative model—at the same time that it reconfirmed its 2018 statement in support.7The BMJ obtained a new resolution dated 1 April that asks the organisation to “issue an interim update to the 2018 policy statement based on the best available evidence to date.”

“The time has passed for yet another systematic review,” says Julia Mason, an Oregon paediatrician and member of SEGM who has submitted several resolutions, including the April 2024 one, to AAP for more evidence based guidance. “We now have a dozen high quality reviews (eight Cass, two NICE, one Swedish, one German) all pointing to significant issues with the purely affirmative model of care,” she says. “Parents and their children are being misled in clinics all over the country. There is no evidence that giving puberty blockers followed by hormones and surgery is lifesaving care, and there is mounting evidence that the harms might outweigh the advantages.” The AAP did not respond to The BMJ’s request for comment.

The American Psychological Association, American Psychiatric Association, and American College of Obstetricians and Gynecologists, which have position statements in support of the affirmative model, have remained silent about Cass. Only the psychology group responded to The BMJ, saying that it is studying the Cass report, but “we stand by the statement.”

Not all relevant professional groups have joined the consensus. Scot Glasberg, past president of the American Society of Plastic Surgeons, now president of the Plastic Surgery Foundation, told The BMJ that the organisation will issue “trustworthy, high quality” guidelines, but “like Dr Cass, we’ve found that the literature is of low quality and low value to dictate surgical care . . . We are trying to be very measured and not get into the difficulty that some of the other organisations have gotten into.” The American Academy of Family Physicians sought to develop a clinical practice guideline in 2020 but hasn’t yet produced one.8 The organisation declined to comment.

Some people in the psychology community are emboldened by Cass to break their silence, even if it means facing hostility from their peers. Brooke Laufer is a clinical psychologist based outside of Chicago and among the 300 clinicians who’ve joined the organisation Therapy First, which promotes psychotherapy as first line treatment for gender exploration. She told The BMJ that she is a politically liberal feminist who has “marched in Pride marches.” Recently, she posted about the Cass review to a listserv of therapists and was reprimanded by several members for promoting “misinformation” and “hate speech.” In February, another listserv member who posted about a Therapy First webinar was met with eight separate complaints to the state medical board.

Laufer says that the American Psychological Association should “gather its integrity and put out a statement that says we’re taking the Cass report seriously and we recommend puberty blockers to be paused unless it’s in the context of a clinical trial.” She adds: “What’s at stake are human lives and a generation of kids. This is about standing up and being adults and saying sorry, we got some of this wrong.”

The American Psychiatric Association met in New York this month for its annual conference. It had just one panel discussion on the topic of gender medicine, about “promoting public policy for evidence based transgender care,” focused on the negative effects of state legislation restricting treatments. In stark contrast, the European Society for Child and Adolescent Psychiatry released a new policy statement on safeguarding gender distressed youth from “experimental and unnecessarily invasive treatments with unproven psychosocial effects.”9

Hesitant media response

US media and the political landscape in general are notoriously polarised. Trusted LGBT+ advocacy groups have been unequivocal about the merits of the affirming model. GLAAD, which journalists founded in the 1980s to combat “grossly defamatory” media reporting about HIV/AIDS, protested the New York Times’s coverage of gender medicine, which has included the voices of former patients who feel they’ve been harmed. Last year, GLAAD parked a truck outside the paper of record’s offices: its electronic billboard stated, “The science is settled.”

Some hoped that Cass would offer an impartial beacon. And a few legacy and left leaning newsrooms covered the report in earnest—Reuters, the New York Times, the Nation, NBC, and the Economist. The Wall Street Journal’s editorial board said that the review “shows wisdom and humility on treatment of young people, in contrast to the ideological conformity in US medical associations.” The Washington Post and Boston Globe also ran opinions that amplified Cass to argue for a more precautionary path forward.

But many outlets historically aligned with advocacy positions have held back on any ink. STAT News, which “delivers trusted and authoritative journalism about health, medicine, and the life sciences,” has so far ignored Cass (as well as The BMJ’s request for comment). So has CNN. Jesse Singal, one of the first American journalists to expose the potential harms of youth gender treatment, reported on his Substack that the legacy news network had recycled the pronouncement that “gender affirming care is medically necessary, evidence based care” in 35 separate articles over the past two years, practically verbatim.10 (CNN did not explain, and did not respond to a query from The BMJ.) “Many outlets dug themselves into a deep hole on this issue by simply acting as stenographers and megaphones for activist groups rather than doing their jobs,” wrote Singal.

Singal has also called out Scientific American for not covering the Cass report, while on 20 April running a question and answer piece with a prominent advocate of gender affirming care titled “Anti-trans efforts use misinformation, epistemological violence, and gender essentialism.” The oldest continuously published magazine in the US, Scientific American, has run several articles favourable to the affirmative model in recent years. In “Why anti-trans laws are anti-science,” written in 2021 and republished in 2023, the magazine’s editors stated that it is “unscientific and cruel” to claim that treatments are “unproven and dangerous” or that “legislation is necessary to protect children.” According to a 2022 article, “What the science on gender affirming care for transgender kids really shows,” data “consistently show that access to gender affirming care is associated with better mental health outcomes.” “Decades of data support the use and safety of puberty pausing medications,” declared one 2023 piece.11

The magazine’s editor in chief, Laura Helmuth, has promoted these pieces on Twitter/X with declarations like, “The research is clear, and all the relevant medical organisations agree”; policies that restrict treatments are “dangerous, cruel, bigoted, and contrary to all the best scientific and medical evidence.” She’s also disparaged inquiries on the subject. In a February 2023 tweet, Helmuth included gender affirming care among a list of “things we don’t need to be both-sidesing, be ‘objective,’ or be ‘just asking questions!’ about.” Neither Helmuth nor the magazine’s publisher, Springer Nature, responded to a detailed email referencing the articles and more than 15 tweets.

A political lens

US reporting in the main is sympathetic with, if not following the lead of, authoritative sources such as the US Department of Health and Human Services (HHS), which informs that “research demonstrates that gender affirming care improves the mental health and overall wellbeing of gender diverse children and adolescents” and calls puberty blockers “reversible.”12 On 24 April, a congressman confronted Xavier Becarra, secretary of the department, about these statements, holding up a thick printed copy of the Cass review. “I can assure you that we look at all studies,” said Becarra. “When we talk about a standard of care, it’s not something we make up. It’s based on what the major medical associations [say].” The US Department of Health and Human Services did not respond to The BMJ’s request for comment.

Rachel Levine, US assistant secretary for health, told National Public Radio in October 2022 that “there is no argument among medical professionals . . . about the value and importance of gender affirming care.” Yale paediatrician Meredithe McNamara, who coauthored a November 2022 commentary in the New England Journal of Medicine titled “Protecting transgender health and challenging science denialism,” told PBS NewsHour the same month, “The evidence base is strong.” McNamara has called puberty blockers “one of the most compassionate things that a parent can consent to for a transgender child,”11 and in testimony to the US Congress, warned that when gender affirming care “is interrupted or restricted, suicide, depression, anxiety, disordered eating, and poor quality of life follow.”13

In professional training, journalists have been led to interpret dissent as part of a “misinformation climate,” as in a two part Poynter Institute webinar called “Transgender coverage: avoiding rhetoric to deliver meaningful journalism,” recorded on 18 April and 2 May. Cass’s final review no doubt qualified as “medical and peer reviewed research findings”—one of the learning goals—yet it went unmentioned in all three hours of discussion. McNamara, the only medical speaker, listed the mental health benefits of gender treatments and showed a chart of five “misinformation themes,” among them “low quality evidence” and “guidelines are not trustworthy.” In part two, when asked about European countries restricting treatment, Jo Yurcaba, a reporter for NBC Out, the LGBTQ section of NBC News, told attendees that “transition related care is highly politicised in Europe, in the same way it is in the US.” These webinars were required viewing for reporters applying for an $11 500 grant for journalists interested in covering transgender issues. A spokesperson for Poynter, which also publishes the fact checking site Politifact, told The BMJ that it “strives to present an accurate, current, and well rounded overview” for journalists in training and that, by 9 April when Cass’s final report was released, “our curriculum and learning objectives had been set and our subject matter experts had prepared their materials.”

So far, outspoken thought leaders have not reconciled their statements with the growing list of systematic reviews that stand in contradiction. In an emailed response to The BMJ, McNamara said that she “noted with great interest, the systematic reviews that the Cass review relied on deemed several of the studies it assessed as ‘moderate’ in quality.” Although other advocates have seized on this apparent discrepancy, it is a known feature of systematic reviews: individual studies within a body of evidence might be rated moderate, yet when taken as a whole, that evidence may still be, as Cass put it, “remarkably weak.”

Some prominent activists attempted to discredit other aspects of Cass, both the review and the person. Alejandra Caraballo, a Harvard Law School instructor with more than 160 000 followers on X, posted in advance of the report’s release that it had “disregarded nearly all studies,” a claim that Cass called “misinformation.” The activist Erin Reed, who has a quarter of a million followers between X and Substack and is a go-to media source, accused Cass of having “collaborated on a trans care ban in Florida.” Cass spoke with a clinical member of the state’s board of medicine as part of her review. On the Majority Report, a podcast with 1.5 million subscribers, Reed said that Cass represents “the playbook for how to ban trans care.”

For science reporters and editors who have repeatedly delivered the “science is settled” boilerplate, these denunciations offer a tempting way around correcting the record. A 10 May article in Mother Jones took that route, casting the report as a political document: “It’s like the DeSantis administration wrote it.”

Medical leaders and media professionals “should engage with the content,” says Abbruzzese, which she notes is in English, freely accessible, and transparent in its rigour. “What the Cass review did was evaluate the gender clinic model of care and concluded that, when delivered in this exceptionalised way, every child who walks through the door is viewed as a trans child who is there to be medically transitioned. Cass concluded that model is fundamentally flawed because these children’s significant pre-existing mental health problems are effectively ignored in the false expectation that transition will cure them.”

“The Cass report is going to stand the test of time,” says Erica Anderson, a clinical psychologist and former president of the US Professional Association for Transgender Health. “I’m already hearing from the boards of directors and trustees of some hospital systems who are starting to get nervous about what they’ve permitted. So I think that’s going to accelerate change within American healthcare.”

In the face of criticism, Cass has been unwavering: “It wouldn’t be too much of a problem if people were saying ‘This is clinical consensus, and we’re not sure.’ But what some organisations are doing is doubling down on saying the evidence is good,” she told the New York Times. “And I think that’s where you’re misleading the public.”


  • Provenance and peer review: Commissioned, peer reviewed.

  • This feature has been funded by the BMJ Investigations Unit. For details see

  • Competing interests: The author declares having contributed a commentary to Scientific American in 2019 that was removed for unspecified reasons following a social media campaign. Helmuth, who became editor-in-chief in 2020, was not involved.