Is the Cass Review actually based on good evidence?

That is exactly the question worth asking. The review set a high bar for evidence quality, which meant excluding many studies that clinicians have relied on for years. Whether that was the right call depends partly on what kind of certainty you think is realistic in this area of medicine. The choices made about methodology shaped the conclusions in ways that are still being debated. What kind of evidence would feel solid enough to you?

How is the Cass Review affecting families right now?

It has changed access, sometimes overnight. Some young people who were receiving care have had treatment paused or withdrawn. Waiting times have lengthened in places, and clinicians report feeling more cautious about supporting transition pathways, even when they believe it is the right approach for a particular young person. The impact is not uniform across the NHS, but it is real and it is happening now. Has this touched your family or someone you know?

The Cass Review is not the final word

Substack 19 December 2025

Examining the Cass Review: evidence, assumptions and impact

The Cass Review has been treated as a settling of the science on gender-affirming care for young people. It is not. A careful look at its methodology, the assumptions baked into its framing, and the real-world consequences of its recommendations shows why critical re-examination is not only reasonable, it is necessary.

The Cass Review has reshaped conversation around gender-affirming care in the NHS, yet questions remain about the evidence foundation on which its conclusions rest. This piece examines the review's methodology, the assumptions embedded within it, and the real-world impact of its recommendations on young people and their families.

Understanding what the review did well, where its scope was limited, and how its findings are being interpreted in clinical practice matters deeply to anyone involved in gender-affirming healthcare. Rather than accepting the review as a final word, there is value in looking again at the evidence, the gaps, and what comes next.

Read the full analysis to explore these questions in depth.

In response to: Why the Cass Review Still Matters, And Why We Must Look Again (Substack)