Cass Review

[last updated 23/01/25]

Wednesday 10 April 2024 saw the long-awaited publication of the final report of the Cass Review. This report was commissioned by NHS England, and provides a review of evidence plus recommendations regarding gender identity services for children and young people.

On publication, the Cass Review’s findings and recommendations were welcomed by the majority of UK media outlets, NHS England, the Editor-in-Chief of medical journal the BMJ, conversion therapy proponents such as SEGM, Sex Matters and Transgender Trend, plus spokespeople for the Conservative and Labour parties, who promised to ensure it will be “fully implemented”.

Conversely, the Review has been extensively criticised by trans community organisations, medical practitioners, plus scholars working in fields including transgender medicine, epidemiology, neuroscience, psychology, women’s studies, feminist theory, and gender studies. They have highlighted problems with the Cass Review that include substandard and inconsistent use of evidence, non-evidenced claims, unethical recommendations, overt prejudice, pathologisation, and the intentional exclusion of service users and trans healthcare experts from the Review process.

This post provides a round-up of links to written commentary and evidence regarding problems with the Cass Review, plus quotes pulled from each. In light of these, I believe that it would be extremely harmful to implement the Review’s findings in full. 

After years of struggle, UK parents successfully lobbied the NHS to start prescribing gender-affirming medical treatments for minors under 16 in 2011. Their success, however, was short-lived.

In April, NHS England released the findings of a four-year inquiry into GIDS led by Dr. Hilary Cass, a pediatrician with no experience treating adolescents with gender dysphoria. On the recommendation of the Cass Review, which was highly critical of adolescent medical transition, the NHS services in England, Wales and Scotland have stopped prescribing puberty blockers for gender dysphoria. The British government also banned private clinics from prescribing them, at least temporarily.

Though there is much more evidence now to support gender-affirming care than in 2008, there is also a much stronger anti-trans movement seeking to discredit and ban such care.

British media coverage has given that movement a big boost in recent years, turning the spotlight away from the realities that trans kids and their families are facing, and pumping out stories nitpicking at the strength of the expanding evidence base for gender-affirming care. Its coverage of the Cass Review followed suit.

US media, unsurprisingly, gave less coverage to the British review, but most of the in-depth coverage followed British media’s model. Underlying this coverage are questionable claims by people with no experience treating minors with gender dysphoria, and double standards regarding the evidence for medical and alternative treatments.

I emphatically reject the author's opinion that "it’s not ridiculous to suggest, for example, that a randomized trial of puberty blockers would be a good idea." (Why not a randomised trial of ambulances? We'll send half of emergency callers an Uber instead.) But he's certainly thorough, and excepts like this are astounding.

The Cass review was an interesting juxtaposition. Some of the scientific arguments were very reasonable, and the York team generally did a decent job with the systematic reviews that informed the document. However, the review itself often positioned bizarre theories about gender dysphoria alongside data and evidence. I’ve recounted quite a few examples of this during my pieces, but I thought I’d share one more that I found recently:

“Research commentators recommend more investigation into consumption of online pornography and gender dysphoria is needed. Some researchers (Nadrowski, 2023) suggest that exploration with gender-questioning youth should include consideration of their engagement with pornographic content.” (Cass review, page 110)

This paragraph suggests that porn can potentially turn children trans. If you look up the reference, it is to this opinion piece from a psychiatrist. The paper itself contains no data connecting gender dysphoria to pornography, but basically argues that teen girls may view porn and become so disgusted with being women that they choose to instead become men. The paper also notes that “Girls affected by autism might be at higher risk because of their reduced mentalization capacities.”, although it does not provide any evidence that this is true.

The author of this opinion piece is a psychiatric trainee who lists their affiliation as Therapy First. Therapy First is an explicitly anti-medication group which campaigns to prevent children from being given hormones or puberty blockers for gender dysphoria - instead, they recommend psychotherapy as the first and in many cases only option. This is not evidence. It’s barely even an opinion. There is no reasonable excuse for the Cass review having included such a completely bizarre and unsubstantiated theory, especially without noting that it is entirely unsupported by even the most vague of evidence.

Since the launch of the Cass Review in 2020, the situation for trans children in the UK has continued to decline (Madrigal-Borloz, Citation2023). In 2022 the UK Minister for Health called for clinicians to look for evidence of “what has caused children to be trans,” citing the Cass Review to claim that “identifying as trans” is likely to be a response to “child sex abuse” (Milton, Citation2022). The Cass Review was cited by the British government to justify plans to exclude trans people from legislation to ban conversion therapy (British Psychological Society, Citation2022). The Cass Review was also cited to justify the closure of existing children’s gender services for England and Wales, with services ceasing to see any new referrals 18 months before replacement services are expected to be operational (Ali, Citation2023). Trans healthcare professionals outside of the UK have critiqued the Cass review (Pang et al., Citation2022) as well as critiquing healthcare policies inspired by the Cass Review such as the NHS’ 2023 draft service specification (WPATH et al., Citation2023).