The British Medical Association has largely reversed its position on the Cass Review into puberty blockers for children — a landmark report the doctors' union had heavily criticized in 2024.
The BMA published its findings after a two-year internal evaluation in a paper titled "Cass Review: Evidence, Interpretation, and Implementation." Report co-author Professor David Strain told The Times the review's author "has been vindicated in the way she approached the data." When asked to name a single one of Hilary Cass's 32 recommendations that the BMA currently opposed, Strain said, "I can't," adding, "she approached an area of significant uncertainty with that prime rule of medicine, of 'first, do no harm.'"
The BMA's shift is significant because its council had, in July 2024, blasted Cass's recommendations as "unsubstantiated," called for a public critique and demanded the lifting of the puberty blocker ban — a move that triggered intense backlash from the BMA's own grassroots medical members. The council subsequently adopted a position of neutrality and launched the internal evaluation group that produced the new paper.
Writing for the Christian Medical Fellowship, Trevor Stammers — a former general practitioner, clinical teacher and past CMF chair — said the BMA's paper amounts to a concession that the evidence base in favor of puberty suppression and gender-affirming hormones for young people is "limited and uncertain."
"Whenever ideology prevails over evidence, people must eventually face up to reality," Stammers wrote. "It's very sad that now the BMA's efforts to discredit Cass' findings have turned out to broadly vindicate them, they still seek to criticise the necessary actions subsequently taken."
That ongoing criticism centers on the BMA's refusal to back a total ban on the treatments. The review group stopped short of endorsing the UK government's absolute statutory ban on the medication, calling it a political "overreach" that threatens the clinical autonomy of prescribing doctors — even as it acknowledged the "known and plausible harms" of puberty blockers.
The Cass Review was an independent analysis of the Gender Identity Development Service run by the Tavistock and Portman NHS Foundation Trust in London. It was led by retired pediatrician Dr. Hilary Cass and commissioned by NHS England. Its findings ultimately led to the closure of the Tavistock clinic, whose centralized service model was deemed unsustainable and lacking a safe, evidence-based foundation.
The review found that clinical staff internationally reported that adolescents "seem to have more complex presentations" and present "with greater mental health and psychosocial needs, as well as additional diagnoses of ASD and/or attention deficit hyperactivity disorder (ADHD)." Data in the report showed that rates of depression, anxiety and eating disorders were significantly higher among those referred to the gender clinic than in the general population.
Baroness Cass also noted in the report that "it is widely accepted that exposure to sexuality is happening at a younger age," adding that the impact on young people's understanding of their sexuality or gender identity "is an area that warrants better exploration and understanding."
Stammers noted that the Cass Review had faced attacks from activists and some academics, including a non-peer-reviewed paper by McNamara et al. that claimed the review contained "serious methodological flaws." He cited the biblical proverb: "Do not testify against your neighbour without cause."
Official figures cited during the clinic's operational history show that 382 children aged up to 6 were referred to the service between 2010 and its clinical wind-down. About 70 were 3 or 4 years old.
