Hilary Cass is a British paediatrician who authored the Cass Review, a 2024 report on gender identity services for children and young people in England. The review has been used to justify restrictions on transgender healthcare across the UK and internationally.
Twitter: @Hilary_Cass
The Cass Review was commissioned by NHS England to examine gender identity services. Its recommendations led to:
- Closure of the Tavistock GIDS clinic
- Restrictions on puberty blockers for trans youth
- Requirements for "holistic assessment" that delay or deny care
- A similar investigation launched into adult gender services
- Justification for similar restrictions internationally
Cass met with notable Gender Critical figures during the review process, including individuals connected to the DeSantis administration in Florida, raising questions about the review's independence.
¶ The "Impossible Standard" Methodology
The review's methodology has been criticized for:
- Creating an impossible evidence standard by which research must be held
- Using that standard to dismiss virtually all evidence supporting gender-affirming care
- Not applying the same standards to anti-trans research
- Purposefully disqualifying supportive studies as "low quality"
After the review was adopted by the Gender Critical movement, Cass began distancing herself from its most extreme interpretations. In an interview with the Kite Trust, she admitted the review "does not conclude that puberty suppressing hormones are an unsafe treatment" — contradicting how it has been used.
Screenshots from December 2024 document Cass's Twitter follows, revealing connections to anti-trans networks:
- TransgenderTrend (@Transgendertrd) — UK anti-trans organization. Notably, TransgenderTrend was one of the three websites used by Lisa Littman to recruit parents for her discredited ROGD study.
- Sarah Phillimore (@SVPhillimore) — British barrister known for anti-trans activism and harassment campaigns
- Israel Defense Forces (@IDF) — Official military account
- Jean Twenge (@jean_twenge) — "iGen" author whose work on social media harm is cited by anti-trans researchers
- Wes Streeting (@wesstreeting) — Labour Health Secretary who has implemented anti-trans policies
The Cass Review exists within the broader anti-trans academic and activist network:
Weaponized by:
Organizational overlap:
- TransgenderTrend (followed by Cass) was a ROGD recruitment site
- Review used similar methodology criticisms as SEGM
- Met with DeSantis-connected figures
The review has been directly connected to increased violence against trans people:
- Prime Minister stated allowing children to socially transition is "not a neutral act"
- #GlinnerWasRight trended after publication
- The murder of Brianna Ghey involved the same transphobic rhetoric the review legitimized
The fact that the author of a supposedly "independent" review:
- Follows TransgenderTrend — an organization involved in producing anti-trans research
- Met with Gender Critical figures during the review process
- Used methodology designed to dismiss supportive evidence
- Is now backpedaling after seeing her work weaponized
...raises fundamental questions about the review's objectivity and purpose.
- Cass Review, NHS England, 2024
- Twitter following screenshots, December 2024
- Erin Reed reporting on Cass meetings with GC figures
- Kite Trust interview with Cass
- Academic criticism of review methodology
- Medium: "Blow it out your Cass" by @transylvania