Understanding the Cass Review’s impact on Gender Identity Services in the UK.

In 2020, Dr. Hilary Cass was commissioned to lead a comprehensive review of Britain’s public health service, the NHS’s gender identity services amidst growing concerns over the adequacy and appropriateness of support provided to transgender youth. The ensuing report, which spanned nearly 400 pages, shed light on inadequacies in medical research related to gender-affirming treatments and the polarised public and professional debates that hinder progress.

Dr. Hilary Cass’s investigation into the NHS’s gender identity services has revealed significant shortcomings in the research and evidence supporting medical interventions for transgender youth, a group increasingly seeking guidance and support. This finding comes at a time when the debate over how best to treat gender dysphoria in children and adolescents has reached a peak in toxicity, affecting professionals and patients alike.


The report begins with a critical assessment of the existing literature, which Cass describes as “remarkably weak.” The review criticises the current state of gender identity research, particularly studies on puberty blockers and hormones prescribed. A systematic review by the University of York highlighted that the evidence base concerning these interventions remains inadequate and is often clouded by misinformation.

Cass emphasises the need for NHS services to adapt to the growing demands by establishing mechanisms to routinely collect and analyse treatment outcomes to better inform clinical practices.

According to the report, the debate around gender identity care was described as highly polarised. Some clinicians advocate for early medical intervention believing that many seeking help will maintain a long-term trans identity. Others argue that this approach may medicalise children who are expressing gender dysphoria as a manifestation of broader psychological issues. This division has created a hostile environment where professionals may feel intimidated to express dissenting views, fearing social vilification and professional isolation.

The Tavistock and Portman NHS Trust’s Gender Identity Development Service (Gids), which has been at the forefront of providing these services since 1989, initially saw only a small number of children each year. However, this number has grown exponentially, especially since the adoption of the Dutch protocol for puberty blockers in 2011. Cass points out that despite the lack of concrete outcomes supporting their efficacy, these treatments became routine. The review calls this a premature adoption of a potentially life-altering medical protocol without sufficient scrutiny.

Furthermore, the demographic profile of those referred to gender services has shifted notably. Historically, transgender individuals presenting in clinics were predominantly males at birth showing persistent patterns into adulthood. Now, a vast majority are teenagers assigned female at birth, complicating previous understandings and approaches to care. This shift coincides with a general deterioration in mental health among young people, a phenomenon exacerbated by social media and other modern pressures.

Dr. Cass also addressed social transitioning, where individuals change their names, pronouns, and appearance to reflect their gender identity. While many studies suggest that social transitioning can have positive effects on a young person’s mental health and social integration, some medical professionals argue it may prematurely lock them into a pathway that leads to medical interventions. Cass advocates for a balanced approach that avoids hastening decisions that could have profound long-term consequences.

In conclusion, the Cass review advocates for a cautious, evidence-based approach to treating gender dysphoria in children and adolescents. It calls for better integration of mental health evaluations and a more conservative approach to medical interventions until more reliable evidence can be gathered but also advocates to ensure that all young people exploring their gender identity can do so in a supportive and non-coercive environment.

In response to the report UK trans youth charity Mermaids issued the following statement:

“Everyone deserves access to timely, supportive and holistic healthcare. However, across all of the UK, the NHS is failing trans youth, with appalling waiting lists of more than six years, virtually no first appointments offered for over a year, and increased politicisation of the support offered to children and young people.

“Trans youth tell us they want services which are accepting and respectful, which offer supportive spaces to explore their gender, and provide access to medical transition if and when they need it.

The Cass Review, an independent review of NHS England gender services for children and young people, published after almost four years, echoes much of this and recognises the current system is failing trans youth.

“We are concerned that some of the language in the report is open to misinterpretation and could be used to justify additional barriers to accessing care for some trans young people.”

“We are pleased the voices and experiences of trans young people appear to have been heard and respected, and we welcome Dr Cass’ calls for trans children and young people, and their families, to be “treated with compassion and respect”. We hope for the same, and for the sharing of clear, accurate information when discussing this topic.

“However, we are concerned that some of the language in the report is open to misinterpretation and could be used to justify additional barriers to accessing care for some trans young people in the same way the interim report has been. We will publish our full analysis of the Cass Review in due course.

“NHS England has published their immediate response to the Cass Review and written to all adult providers, explaining the changes they plan to make in the short to medium term. Very few of these will have an immediate effect on children and young people, and we will keep trans young people and their families informed about any changes that might impact them.

“In the meantime, we call on NHS England, and the NHS across the UK, to resist pressures from those who seek to limit access to healthcare, listen to trans youth directly, and act urgently to provide gender services which are timely, supportive and holistic.