The Tavistock and Portman NHS Trust, home of the GIDS service until it was closed. Photo Workers.
The Cass Review into the care of young people questioning their gender identity represents a triumph of a materialist, evidence-based approach over zealotry and dogma…
The rigorous approach taken by Dr Hilary Cass in her review of gender identity services is a turning point, not only in the care of such young people, but in the public discussion of these questions.
There had been a dramatic rise in cases of gender dysphoria (a state of feeling very uneasy about one’s gender) among young people. And then, a growing controversy about the way young people were being treated by the Gender Identity Development Service (GIDS), based at the Tavistock and Portman NHS Foundation Trust in London.
In autumn 2020 NHS England and NHS Improvement (now merged) commissioned Cass, an eminent paediatrician, to lead the Independent Review of Gender Identity Services for Children and Young People.
GIDS was established in 1989 at St George’s, moving to the Tavistock in 1994. It took referrals from across England. In the early years it saw small numbers, fewer than ten a year, and predominantly prepubertal boys. Only a few would be referred for hormonal treatment when they reached the age of sixteen.
In the late 1990s and 2000s doctors in the Netherlands developed the Dutch protocol, as it was known. Patients, who had to be at least 12 years old with lifelong gender dysphoria and no serious co-existing psychiatric conditions, could receive gonadotrophin-releasing hormone agonists, generally known as “puberty blockers”. The rationale for this treatment was that it would buy time to think, so that the young people could be helped, over time, to an informed decision about their future.
The use of puberty blockers is controversial. They reduce bone density in the short term, which can contribute to poor bone health in adulthood and old age, leading to osteoporosis. They can also increase the risk of developing hormone-dependent cancers later in life.
And, most importantly, they can impact fertility in later life. When the use of puberty blockers may cause long-term adverse effects, the case for using them becomes weaker.
But in the USA an approach developed known as the affirmative model. This theorised that a child of any age could know its “authentic” gender identity, and should be supported to transition at any stage of development. This perspective gained ground at GIDS, and in 2014 the service began an “early intervention” policy, allowing children to be readily referred for puberty blockers at age 12.
Clinical practice at GIDS changed from an approach to buy time, and to exclude patients with serious psychiatric conditions, into one where puberty blockers became the default treatment. This was favoured by clinicians who supported the affirmative model and, increasingly by patients themselves, and, sometimes, their families.
Change in referrals
The Cass review describes a remarkable change in referrals to GIDS. In 2009 the service received 51 referrals, with a majority of boys. By 2016 there were 1,766 referrals, nearly 70 per cent girls. Waiting lists exploded.
Not only was GIDS unable to cope with demand, but increasingly clinicians in the service tried to raise safety concerns. In 2018, one of the consultant psychiatrists and a staff representative on the Tavistock’s council of governors, Dr David Bell, submitted a report to the trust board, expressing concern at an “excessively affirmative” approach, and concluding that GIDS was not fit for purpose.
He also pointed out how the whole trust had come to depend on guaranteed income from GIDS, which came to make up over a fifth of total income.
Other staff shared his concerns. Some even resigned.
In 2021 the Care Quality Commission found GIDS to be inadequate. The CQC cited: a waiting list of over 4,600; poor management of risk of vulnerable patients; poor record keeping, with no care plans; variations in clinical approach between staff; inconsistent recording of patients’ consent, competence and capacity; and staff unable to raise concerns without fear of retribution.
A court case (Bell v Tavistock) in 2020 was brought by a GIDS patient on the question of whether children under 16 could give consent to puberty blocking treatment. Ultimately the Court of Appeal found against the patient, but the case helped to shift the climate of opinion and contributed to the NHS setting up the Cass review.
The puberty blocker lobby vociferously claimed that a ban on puberty blockers would lead to a large increase in suicides among young gender dysphoria patients.
But a review by Professor Louis Appleby, the Department of Health and Social Care adviser on suicide prevention, found that there was no data to support this claim.
Appleby castigated those who turned the issue into a social media furore: “The way that this issue has been discussed on social media has been insensitive, distressing and dangerous, and goes against guidance on safe reporting of suicide.”
Unsafe
The interim report from Cass appeared in February 2022. It found that GIDS was not safe or viable in the long term. She pointed out that many of the patients presenting to GIDS clinicians had other co-existing complex medical conditions and needs, but once diagnosed with gender-related distress, those clinicians adhering to the affirmative approach would tend to neglect these other issues.
NHS England closed GIDS, and replaced it in the short term with regional centres based in children’s hospitals. Dr Cass was insistent that specialist services should be developed around the country, working to common standards.
‘A review found no data to support the claim that a ban on puberty blockers would lead to a large rise in suicides…’
The final report of the Cass Review was published in April 2024. It insists on the principles of evidence-based medicine. Treatments should be guided by the best available evidence, the patient’s preferences and values, and the clinician’s expertise and experience. Cass and her team had commissioned a series of systematic reviews of the evidence, and heard from young people, parents and carers, and a wide range of professionals.
The report makes 32 recommendations, on how care should be provided, both by clinicians and its organisation within the NHS, and on future research. In response NHS England announced that puberty blockers would not be prescribed, except in clinical trials.
The review received widespread clinical and academic support. Yet in July 2024 the British Medical Association’s (BMA) UK Council voted to “publicly critique” the review, claiming its recommendations were “unsubstantiated”.
A whistle blower brought this to the medical profession’s attention. It was revealed that while 21 members of the council voted to oppose the Cass review, 13 abstained and 11 voted against the motion.
A grassroots campaign among BMA members, “Not In Our Name BMA”, took off and quickly gathered over 1,500 signatories to an open letter to the chair of the BMA Council. Questions of treatment protocols, as covered by the review, are usually the domain of the medical Royal Colleges, not the BMA, the trade union. The BMA Council retracted its position, changing it to one of neutrality.
The battle is not over. Proponents of the affirmative approach continue to argue that all the effects of puberty blockers are reversible. A few critiques of Cass have appeared online too.
The authors of a paper published early in February 2025 analysed the critiques published to date and concluded that they “have contained incorrect or inadequately contextualized claims”. None of them cited any of the recent systematic reviews, the authors pointed out.
Meanwhile, Kiera Bell, who brought the 2020 court case, is campaigning for further restrictions on hormone treatments for young people.