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." She is now calling publicly for a clinical trial of puberty-suppressing hormones to go ahead — even though her own review led to a blanket ban on them.

The statement, reported by the BBC on 22 June 2026, shows a split between what the review actually recommended and what policy now says. The review examined NHS gender identity services and found "remarkably weak" evidence on puberty blockers. Its final report came out in April 2024.

The review said one specific thing: puberty-suppressing hormones should only be given to under-18s as part of a proper medical study. The NHS had already stopped routine prescriptions in March 2024. Then in December 2024, ministers announced the ban would be permanent.

What the review asked for, and what happened instead

Here is the key difference: the Cass Review said use a controlled research programme. It did not say ban them forever. The permanent ban announced by the government actually stops the research that the review said was needed.

Dr Cass is now pointing this out. She is not changing her mind about what the review found. Instead, she is defending a central idea from her own work: when evidence is weak, you need to gather better evidence in a proper way. You do not avoid the problem by banning everything.

The government's October 2025 response agreed with Cass that the evidence is not strong enough to prescribe outside a research study. But now it seems the government and Cass disagree on what should happen next.

Why this matters

Different parts of the UK (Scotland, Wales, and Northern Ireland) handle healthcare differently. England's permanent ban does not automatically apply to the other three nations, though prescribing practices have changed across the whole NHS.

Parliament may now face pressure to separate two different things: a complete ban, and the controlled research programme the review actually suggested. They are not the same. One stops the conversation. The other — a properly run clinical trial with safeguards — follows from what the review itself said: if the evidence is weak, you test it properly, rather than just freezing the situation as it is.

The question for government now is whether it sees Dr Cass's statement as something worth thinking about, or as awkward timing. That may depend on where that trial currently stands, and on how much the government still relies on the review's findings when making other decisions about gender healthcare.

What is certain is this: Dr Cass has put herself in a difficult position. She is now asking for conditional clinical access at the exact moment the government is using her review to block it.