Supporters of the NHS Puberty Blocker Study Are Still Missing the Point

By Carrie Clark

Earlier this year, Genspect UK published a comprehensive report on the ethical and practical challenges faced by the NHS puberty blocker study. We concluded that those challenges were insurmountable, and wrote to the King’s College study team and the Health Secretary asking them to address the issues raised in our report. The replies we received were not reassuring. Our concerns were brushed aside, and there was no indication that those responsible for the study were grappling with the huge questions it raises.

Ethical Concerns Over the NHS Puberty Blocker Study

Despite news that the study design has now been submitted for final research approval, we seem no closer to hearing the answers to those questions. In fact, much commentary on the puberty blocker study seems to ignore them entirely, with discourse often breezing past the obvious moral complexities involved in interrupting healthy adolescent development. Recent comments by evidence-based medicine specialist Professor Susan Bewley, published on the Gender Clinic News Substack, are a case in point.

To her credit, Professor Bewley agrees with Genspect that it would be unconscionable to proceed with a new trial of puberty blockers before completing the data linkage study (DLS). Recommended by the Cass Review, the DLS would track the outcomes of the 9,000 children treated by the disgraced Tavistock Gender Identity Development Service. Some 2,000 of those young people are believed to have taken puberty blockers, and we must find out what has happened to them before we expose any more children to the well-documented risks of these drugs.

The Critical Need for the Data Linkage Study (DLS)

The total institutional malaise regarding the DLS has been incredibly disappointing to see. Despite the implications this may have for the ethics of any new trial of puberty blockers, Freedom of Information requests show that the DLS has occupied only a tiny fraction of the NHS Children and Young People’s Gender Dysphoria Research Oversight Board’s time. The Board has instead focused on advancing the new puberty blocker study as rapidly as possible. Health Secretary Wes Streeting, rightly praised for prioritising the safety of young people by introducing the puberty blocker ban, has given no public updates about when the results of the DLS may be available. It is hard to overstate just how irresponsible it would be for the NHS to proceed with a new puberty blocker study without taking account of what the DLS can tell us about the well-being of people who have already taken them. As Professor Bewley says, “I don’t see how they [the puberty blocker study team] can even be designing good research without that information.”

DLS aside, however, Genspect’s position on the puberty blocker trial diverges sharply from Professor Bewley’s. While Genspect believes that it would be unethical to conduct a trial at all, Professor Bewley argues that it would be unethical not to, stating that, “Other trials of more dangerous medications—for example, chemotherapy and radiotherapy for childhood cancers—have been ethical to test”. Professor Bewley doesn’t mention the critical flaw in this analogy. Childhood cancer can be fatal, and the risk-benefit analysis for any proposed treatment must account for the likely death of the child without medical intervention. By contrast, far from being fatal, gender related distress has remarkably high natural recovery rates. The acceptable threshold of risk is obviously far lower for a condition that is naturally remitting in the majority of patients. There is simply no comparison to be made between these two conditions, and given how much unnecessary fear has been caused by misinformation about gender distressed youth and suicide, public figures have a particular responsibility not to misrepresent gender related distress as a life-threatening condition.

Flawed Analogies and Methodological Issues

Still more puzzling are Professor Bewley’s beliefs about how the puberty blocker study could be made methodologically sound. So far, puberty blockers have not been tested in double blind, randomised control trials (RCTs), considered the ‘gold standard’ of evidence-based medicine. Double-blind RCTs aim to reduce bias by ensuring that neither participants nor study staff know who has been assigned to the intervention group or the placebo group. It should be immediately apparent that it simply isn’t possible to blind a study of puberty blockers. Children assigned to the placebo group will go through natural puberty, with all of the readily observable physical and emotional changes that entail, while their peers in the intervention group will not.

Bizarrely, Professor Bewley suggests this difficulty could be overcome by giving participants assigned to the placebo arm a fake puberty blocker injection. It’s not clear how she believes a fake injection could possibly conceal the growth of breasts and body hair, the start of menstruation, or the deepening voice. Common sense suggests that the trial will have been unblinded within a few short months of starting, thereby defeating the entire purpose of blinding in the first place. Professor Bewley tries to brush this off, claiming that “even if they [study participants] work it out later, this advances knowledge about the impacts of the drugs”. This is effectively an admission that no puberty blocker study, however it is designed, will be capable of producing the high-quality evidence that would be needed to justify the use of such a radical intervention on vulnerable young people. As Genspect argued in our report, it cannot be considered acceptable to expose more young people to the documented risks of puberty blockers simply in pursuit of further low-quality, inconclusive evidence.

The impossibility of conducting high-quality research on gender interventions points to the fundamentally subjective nature of both the diagnosis of ‘gender dysphoria’ and the beliefs people hold about how it should be treated. Professor Bewley suggests a list of research questions that the puberty blocker study might aim to address, but overlooks the fact that each is underpinned by the assumption that blockers are an appropriate and effective treatment. Questions about optimal dosing, the most beneficial age at which to commence blockers, and differences between young people with childhood or adolescent onset presentations all take it for granted that there is pre-existing agreement about the purpose of treatment and a clear indication for using risky, experimental interventions on physically healthy children.

Before quibbling over dosage and timing, we need to address the assumption that radically modifying children’s bodies in service of their ‘embodiment goals’ is an appropriate response to subjective feelings of mental and emotional distress. None of the existing research indicates that it is. Genspect’s report could not identify an evidence-based indication for the use of puberty blockers in gender distressed children, and the Cass Review itself “found that there is no clarity about the treatment aims of puberty suppression”. The impossibility of conducting truly objective research on this issue only makes it more critical that we tackle the complex moral questions posed by so called ‘gender affirming’ care, questions its’ advocates still have yet to answer.

It now seems almost inevitable that the NHS puberty blocker study will go ahead without ever substantively wrestling with those questions. A new cohort of gender distressed young people will be exposed to all the cognitive, emotional, and physical harms of blockers in the name of ‘research’, even though we can predict with some confidence that the study will not be capable of generating the decisive, high-quality evidence needed to break the deadlock on so-called ‘gender affirming’ care. Some of the young people who take part in the study will no doubt be harmed, joining the growing number of detransitioners for whom the NHS still provides no specialist healthcare pathway. In ten years’ time, when those young people are telling their stories in Genspect’s Beyond Trans support groups, people who supported the puberty blocker study will not be able to say that we didn’t warn them.

Carrie Clark is a writer and researcher in the UK. She runs the Healix Substack, a platform for people in the UK who have been harmed by prescribed psychiatric drugs, and works with the Inner Compass Initiative to raise awareness of non-pharmaceutical approaches to managing mental and emotional distress. She is a co-editor of The Gender Framework, an evidence based guide to understanding gender related distress.


Genspect publishes a variety of authors with different perspectives. Any opinions expressed in this article are the author’s and do not necessarily reflect Genspect’s official position. For more on Genspect, visit our FAQs.