Researchers in the UK have announced two clinical trials to investigate the impact of puberty blockers on young people with gender incongruence. The studies follow the 2024 Cass review of NHS gender identity services, which found 'insufficient evidence' about the effects of puberty suppression on psychological wellbeing, cognitive development, and physical health.
The Pathways Trial will recruit approximately 226 young people over three years. Participants, aged from 10-11 for biological females and 11-12 for biological males (with a maximum of 15 years and 11 months), will be randomly assigned to either start puberty blockers immediately or after a one-year delay. All will receive additional care and support, with their health monitored for 24 months.
The second study, Pathways Connect, will involve around 150 trial participants and 100 non-treated young people with gender incongruence. It will use MRI brain imaging and cognitive tests to analyse neurological effects. The team expects results in at least four years.
Chay Brown of TransActual raised ethical concerns, calling the trial 'coercive' as it is the only NHS route to puberty blockers. He criticised the randomised design for causing distress to those delayed. Professor Emily Simonoff, chief investigator, noted that puberty blockers should have been studied earlier and that clinical trials are standard for new medications.
