Two studies to investigate the impact of puberty blockers in young people with gender incongruence have been announced by researchers in the UK after an expert view said gender medicine was “built on shaky foundations”.
Puberty blockers were originally used to treat early onset puberty in children but have also been used off-label in children with gender dysphoria or incongruence.
However, the 2024 Cass review of NHS gender identity services for children and young people found there was “insufficient/inconsistent evidence about the effects of puberty suppression on psychological or psychosocial wellbeing, cognitive development, cardio-metabolic risk or fertility”.
NHS England subsequently announced children with gender dysphoria would no longer receive puberty blockers as routine practice, with their use confined to research settings.
Researchers have now announced two new studies as part of a wider “Pathways” programme to explore the impact of such drugs among young people being treated in specialist NHS children and young people’s gender services.
Pathways Trial is a clinical study that will recruit an estimated 226 young people over the next three years. The youngest participants are expected to be 10 to 11 for biological females and 11 to 12 for biological males – although the team note the rigorous selection process means participants will probably be older – and the upper age limit for joining the study is 15 years and 11 months.
Participants will be randomised to immediately start puberty blockers or begin using the drugs after a year’s delay, alongside a wider package of care and support.
In all cases their health, wellbeing and development will be carefully monitored for 24 months, with each participant reviewed individually and clinically at the end of the trial to look at their ongoing care needs – something the team say may include remaining on puberty blockers.
Participants’ results will also be compared with those from another group of young people with gender incongruence who are not receiving puberty blockers.
The second study, called Pathways Connect, will involve about 150 of those taking part in the Pathways Trial, as well as about 100 young people with gender incongruence who are not receiving puberty blockers, undergoing MRI brain imaging, with the findings analysed against their results from cognitive tasks and tests.
The team say it will be at least four years before the results of the studies are known.
Chay Brown, the health director for the advocacy group TransActual, raised ethical concerns about the trial, describing it as “coercive in nature”.
“It is, and will be for a long time to come, the only means that young people have of accessing puberty blockers through the NHS,” he said.
“Worse, the fact that it is a randomised controlled trial, which means leaving some of the young people waiting an extra year for puberty suppression, is not a neutral act. Those in that group will experience distressing pubertal changes that those in the other group will not.
“While we are glad that some young people will be able to access the care they need without being criminalised, we fear that this is overall bad news for young trans people in the UK.”
Emily Simonoff, a professor of child and adolescent psychiatry at King’s College London and chief investigator of the new studies, said it was often the case that new medications were available only through a clinical trial.
“One might want to argue that puberty suppression should never have been made available to young people outside of a clinical trial some 10 or 15 years ago, and the most ethical thing would have been to do a trial at that point in time,” she said.
