Dr Hilary Cass has said she is "absolutely convinced that more children will be harmed if we don't do the trial than if we do," calling publicly for a clinical trial of puberty-suppressing hormones to proceed despite the blanket ban her own review prompted.

The statement, reported by the BBC on 22 June 2026, exposes a gap between what the Cass Review actually recommended and the policy that followed it. The review, commissioned to examine NHS gender identity services, found "remarkably weak" evidence on puberty blockers. Its April 2024 final report contained 32 recommendations across the service.

One recommendation stood out: puberty-suppressing hormones should be prescribed to under-18s only within a formal research protocol. The NHS had already halted routine prescriptions in March 2024. The government then moved to make this official — and in December 2024, ministers announced the ban would become indefinite, citing expert advice.

The difference between what Cass proposed and what happened

Here is the practical tension: the Cass Review recommended a tightly controlled research pathway. It did not propose a permanent ban. The indefinite prohibition announced in December 2024 effectively closes off that research route — the very pathway the review had endorsed as the only way to resolve the evidence gap.

Cass is now drawing attention to this difference. Her position is not a U-turn on the review's findings. Rather, it defends one of the review's core principles: that weak evidence demands that we generate better evidence under controlled conditions, not avoid the question by banning everything.

The government's October 2025 consultation outcome confirmed the administration reads the evidence base as too limited to justify prescription outside research — a view that aligns with Cass's methodology but, it now emerges, not her judgment on what follows.

Why this matters across the UK

Gender services are a devolved responsibility in Scotland, Wales, and Northern Ireland. Holyrood (the Scottish Parliament), the Senedd (Welsh Parliament), and Stormont (Northern Ireland Assembly) have each shaped their own responses to the review. England's indefinite ban does not automatically extend to the other nations, though prescribing practices have shifted NHS-wide.

Westminster faces fresh pressure to clarify the distinction between a complete prohibition and the structured research access the review actually outlined. These are different policies. One forecloses inquiry. The other — a properly designed randomised controlled trial with ethical oversight — is what the review's own logic points towards: if evidence is weak, generate better evidence under controlled conditions rather than institutionalising the uncertainty.

The question now is whether ministers treat Cass's intervention as a technical point worth reconsidering or as an awkward political complication. That will partly depend on what status the trial currently holds and partly on how much weight the government still invests in the review's authority on other aspects of transgender healthcare.

What is clear is that Cass has positioned herself in an uncomfortable spot: she is now advocating for conditional clinical access at the very moment the government uses her review to deny it.