Dr Hilary Cass on RNZ National: A Detailed Review
FACT-CHECK ANALYSIS | Dr Helen Webberley, Gender Specialist and Medical Educator
Dr Cass gave an interview to New Zealand radio. I have fact-checked her claims.
If you have a trans child, if you work in healthcare, or if you have simply been trying to follow the debate about puberty blockers and gender-affirming care, you have almost certainly come across the Cass Review. It is a report published in April 2024 for NHS England, and it has been used to justify the banning of puberty blockers for gender-diverse young people, not only in the UK but in countries around the world.
Dr Hilary Cass, who led the review, has since given a series of media interviews, and she has spoken to RNZ National in New Zealand as that country’s government considers following the UK’s example.
First, a little context
New Zealand’s government moved to ban puberty blocker prescriptions for new patients just before Christmas 2025, citing the Cass Review among its reasons. An urgent High Court injunction paused that ban, and a judicial review is set for May 2026. Dr Cass gave this interview in that context, speaking directly to a New Zealand audience about what she found, what the science shows, and whether the ban is a good idea.
She is articulate and she comes across as thoughtful. She also says some things in this interview that I cannot let pass without comment. So let us go through them together.
I want to talk you through what she said, what the evidence actually shows, and where I think the record needs to be set straight. I am not doing this to be combative, and I want to be honest that some of what Dr Cass said is reasonable. But some of it is not supported by the evidence, and some of it is misleading in ways that matter deeply to the young people whose lives are being shaped by these decisions.
Fact Check Verdict Key
What follows is a structured fact-check of the statements made by Dr Hilary Cass in her interview on RNZ National1, recorded in early 2026. The interview took place in the context of New Zealand’s High Court challenge to a government ban on new puberty blocker prescriptions for gender-diverse young people, and New Zealand’s pending judicial review, set for May 2026.
