Mick Hartley

The effects of puberty blockers could hardly be of more profound significance these days. They've been handed out like sweeties to young "trans kids" at places like the Tavistock Clinic with the blithe assurance that they're reversible and absolutely fine, but, given how powerful they are, that has to be highly questionable to say the least. They effectively block the production of hormones – a kind of chemical castration -  during the key developmental phase of growing up. In addition, some studies have shown a negative impact on cognitive function in animals, and possibly in humans. This is serious stuff. Shouldn't more research be done before we risk this kind of powerful medical intervention on vulnerable children? 

Sallie Baxendale is a consultant clinical neuropsychologist and a professor of clinical neuropsychology at University College London, so she has some authority here, but when she pointed all this out, well, nobody seemed that interested:

Last year, I wrote a paper to summarise the results of these studies. The paper explained in relatively simple terms why we might think that blocking puberty in young people could impact their cognitive development. In a nutshell: puberty doesn’t just trigger the development of secondary sex characteristics; it is a really important time in the development of brain function and structure. My review of the medical literature highlighted that while there is a fairly solid scientific basis to suspect that any process that interrupts puberty will have an impact on brain development, nobody has really bothered to look at this properly in children with gender dysphoria.

I didn’t call for puberty blockers to be banned. Most medical treatments have some side effects and the choice of whether to take them depends on a careful analysis of the risk/benefit ratio for each patient. My paper didn’t conduct this kind of analysis, although others have and have judged the evidence to be so weak that these treatments can only be viewed as experimental. My summary merely provided one piece of the jigsaw. I concluded my manuscript with a list of outstanding questions and called for further research to answer these questions, as every review of the medical literature in any field always does….

I was surprised at just how little, and how low quality, the evidence was in this field. I was also concerned that clinicians working in gender medicine continue to describe the impacts of puberty blockers as “completely physically reversible”, when it is clear that we just don’t know whether this is the case, at least with respect to the cognitive impact. But these were not the only troubling aspects of this project. The progress of this paper towards publication has been extraordinary, and unique in my three-decades-long experience of academic publishing.

Yet although her paper has now been accepted for publication "in a well-respected, peer-reviewed journal", that was after three rejections. "I have never encountered the kinds of concerns that some of the reviewers expressed in response to my review of puberty blockers." These included the suggestion that she should "focus on the positive things that puberty blockers could do", and that she appeared to show an alarming "bias" towards caution.

I sincerely hope that any arrest in brain development associated with puberty blockers is recoverable for young trans and gender diverse people, who are already facing significant challenges in their lives. I would welcome any research that indicates that this is the case, not least for the significant insights that would present to our current understanding of puberty as a critical window of neurodevelopment in adolescence. Puberty blockers almost invariably set young people on a course of lifetime medicalisation with high personal, physical and social costs. At present we cannot guarantee that cognitive costs are not added to this burden. Any clinician claiming their treatments are “safe and reversible” without evidence to back it up is failing in their fundamental duty of candour to their patients. Such an approach is unacceptable in any branch of medicine, not least that dealing with highly complex and vulnerable young people.