What are the key findings of the NHS gender identity review?

A review into the NHS’s gender identity services has found that children and young people have been let down by a lack of research and evidence on medical interventions in a debate that has become exceptionally toxic.

Dr Hilary Cass said her report was not about defining “what it means to be trans” or “undermining the validity of trans identities”, but about “how best to help the growing number of children and young people who are looking for support from the NHS in relation to their gender identity”. Here are the review’s key findings.

The evidence

“This is an area of remarkably weak evidence,” Cass writes in the foreword to her 398-page report.

Despite that, she adds: “Results of studies are exaggerated or misrepresented by people on all sides of the debate to support their viewpoint. The reality is that we have no good evidence on the long-term outcomes of interventions to manage gender-related distress.”

Related: ‘Children are being used as a football’: Hilary Cass on her review of gender identity services

When Cass began her inquiry in 2020, the evidence base, especially about puberty blockers and masculinising and feminising cross-sex hormones was “weak”. That was exacerbated by the existence of “a lot of misinformation, easily accessible online, with opposing sides of the debate pointing to research to justify a position, regardless of the quality of the studies.”

Cass commissioned York University to undertake systematic reviews of the evidence on key issues, such as puberty blockers. It found that “there continues to be a lack of high-quality evidence in this area”. York academics, as part of their research, tried to document the outcomes seen among the 9,000 young people who the Tavistock and Portman NHS trust’s gender identity development service (Gids) treated between 2009-2020. However, it was “thwarted by a lack of cooperation from [six of England’s seven NHS] adult gender services”.

The new NHS services for these young people must routinely collect evidence of what treatments work, and learn from them to improve clinical practice, the report states.

The debate

Cass acknowledges that the discussion around how to care for such young people is polarised, both among health professionals and in wider society. For example, some clinicians believe that most people who present to gender services “will go on to have a long-term trans identity and should be supported to access a medical pathway at an early stage”.

Related: Mother criticises ‘agenda from above’ after release of Cass report

“Others feel that we are medicalising children and young people whose multiple other difficulties are manifesting through gender confusion and gender-related distress. The toxicity of the debate is exceptional,” the report says.

Cass has been criticised for talking both to groups who support gender affirmation – the medical approach – and also those who believe greater caution is needed. Some experienced doctors who have offered different viewpoints have been “dismissed and invalidated”, she says.

“There are few other areas of healthcare where professionals are so afraid to openly discuss their views, where people are vilified on social media and where name-calling echoes the worst bullying behaviour. This must stop.”

The toxicity of debate has made some clinicians fearful of working with these young people.

The Tavistock and Portman NHS Trust

When its Gids service was set up in 1989, it saw fewer than 10 children a year, mainly birth-registered males who had not reached puberty. Most received therapy and only a few hormones from the age of 16.

But in 2011 the UK began trialling the use of puberty blockers, as a result of the emergence of “the Dutch protocol”, which involved using them from early puberty. However, a study undertaken in 2015-16, although not published until 2020, shows “a lack of any positive measurable outcomes”.

“Despite this, from 2014 puberty blockers moved from a research-only protocol to being available in routine clinical practice.” This “adoption of a treatment with uncertain benefits without further scrutiny” helped increase the demand among patients for them, the report finds.

An NHS England review in 2019, which examined the evidence on medical intervention and found evidence of its effectiveness to be “weak”, led to Cass being asked to undertake her review.

Changing patient profile

Referral rates to Gids have rocketed since 2014, but there has also been a shift in the profile of those using services. For centuries transgender people have been predominantly trans females who present in adulthood. Now the vast majority are teenagers who were registered as female at birth.

An audit of discharge notes of Gids patients between 1 April 2018 and 31 December 2022 showed the youngest patient was three, the oldest 18, and 73% were birth-registered females, according to the review, which tries to discover why things have changed so dramatically.

One area it explores is the deterioration in mental health among young people, and the links with social media, which have brought pressures to bear on them that no previous generation has experienced.

“The increase in presentations to gender clinics has to some degree paralleled this deterioration in child and adolescent mental health,” the review says. “Mental health problems have risen in both boys and girls, but have been most striking in girls and young women.”

Youngsters who present with gender identity issues to services may also have depression, anxiety, body dysmorphia, tics and eating disorders, as well as autism spectrum disorder (ASD) and/or attention deficit hyperactivity disorder (ADHD). Referrals to Gids are also associated with higher than average rates of adverse childhood experiences, the review says.

“There is no single explanation for the increase in prevalence of gender incongruence or the change in case-mix of those being referred to gender services,” the review says, concluding instead that gender incongruence is a result of “a complex interplay between biological, psychological and social factors”.

Transitioning

Young people’s sense of their identity is not always fixed and can evolve over time, Cass says.

“Whilst some young people may feel an urgency to transition, young adults looking back at their younger selves would often advise slowing down,” the report says.

“For some, the best outcome will be transition, whereas others may resolve their distress in other ways. Some may transition and then de/retransition and/or experience regret. The NHS needs to care for all those seeking support.”

Social transitioning

Social transitioning is the process by which individuals make social changes in order to live as a different gender, such as changing name, pronouns, hair or clothing, and it is something that schools in England have been grappling with in recent years.

According to the Cass review, many children and young people attending Gids have already changed their names by deed-poll and attend school in their chosen gender by the time they are seen.

The review says research on the impact of social transition is generally of a poor quality and the findings are contradictory. Some studies suggest that allowing a child to socially transition may improve mental health and social and educational participation.

Others say a child who is allowed to socially transition is more likely to have an altered trajectory, leading to medical intervention, which will have life-long implications, when they might otherwise have desisted.

“Given the weakness of the research in this area there remain many unknowns about the impact of social transition,” the review concludes. “In particular, it is unclear whether it alters the trajectory of gender development, and what short- and longer-term impact this may have on mental health.”

The review recommends that parents should be involved in decision making, unless there are strong grounds to believe this may put a child at risk, and where children are pre-puberty, families should be seen as early as possible by a clinician with relevant experience. It also suggests avoiding premature decisions and considering partial rather than full transitioning as a way of keeping options open.

Future care

The report says that in the future any young person seeking NHS help with gender-related distress should be screened to see if they have any neurodevelopmental conditions, such as autism spectrum disorder, and also given a mental health assessment.

NHS England has already in effect banned the use of puberty blockers because of limited evidence that they work. Cass found that there is “no evidence that puberty blockers buy time to think”, which their advocates have claimed. There is also “concern that they may change the trajectory of psychosexual and gender identity development” as well as pose long-term risks to users’ bone health, the review says.

There is also a lack of evidence to prove that masculinising and feminising hormones improve a young person’s body satisfaction and psychosocial health, and there is concern over the impact on fertility, growth and bone health. There is also no evidence they reduce the risk of suicide in children, as their proponents have claimed.

Lastly, the evidence base showing whether psychosocial interventions – therapy – work for those who do not undergo hormone treatment is “as weak” as for puberty blockers and cross-sex hormones.

All this means that there is “a major gap in our knowledge about how best to support and help the growing population of young people with gender-related distress in the context of complex presentations”.