Dr. Hilary Cass, the author of an independent review into gender identity services for children and young people in England, has stated that clinical trials are necessary to properly understand the long-term impacts of prescribing puberty blockers. This recommendation follows the decision by NHS England in March 2024 to halt the routine prescription of puberty-suppressing hormones for children experiencing gender distress due to a lack of robust clinical evidence.
Addressing The Evidence Gap
The Cass Review, which completed its final report in April 2024, concluded that there was remarkably weak evidence regarding the long-term physical and psychosexual outcomes for minors receiving these medical interventions. By transitioning to a clinical trial model, healthcare authorities aim to ensure that children receiving treatment are monitored within a structured, scientific framework rather than a routine care setting.
The purpose of doing it through a research study is that it enables us to look at the longer-term outcomes and to ensure that we are actually doing good rather than unintended harm.
Dr. Cass noted that collecting high-quality data is vital to inform future care strategies and patient safety, as the current evidence base remains insufficient to support widespread usage. NHS England is currently in the process of establishing a research protocol to facilitate this transition.
Protecting Patient Wellbeing
The move to restrict access to puberty blockers outside of research trials reflects a wider effort by health authorities to navigate the balance between rapid access to gender-affirming care and established medical safety standards. Concerns previously raised about these professional services centred on the significant ‘evidence gap’ regarding the lasting effects of treatment paths that begin in childhood or early adolescence.
The implementation of this trial approach is intended to mitigate risks while allowing health professionals to build a stronger, more reliable evidence base for future clinical practice. Further details regarding the initiation of these formal studies are expected to be announced by the NHS as part of its ongoing service reform.