British Medical Association Ends Formal Opposition to Cass Review After Completing Its Own Evaluation

The British Medical Association announced on or before May 7 2026 that it no longer opposed the Cass Review after concluding its own evaluation of the independent report on gender services for children. Dr. Hilary Cass spent four years gathering evidence after Britain's National Health Service commissioned the investigation in 2020 into the medical research supporting gender affirming care for children.

Her findings were published in April 2024. The Cass Review concluded that the medical research behind many aspects of gender affirming care for kids was weak. Dr. Hilary Cass stated there was concern that puberty blockers may change the trajectory of psychosexual and gender identity development.

Most patients who receive puberty blockers go on to take cross-sex hormones. She said the NHS should exert extreme caution in giving out cross-sex hormones to under-18s. The Cass Review concluded there is a lack of high-quality research on the effectiveness of cross-sex hormones for under-18s.

It called for an overhaul of NHS gender services and a move away from a medical pathway that had led to thousands of children being put on powerful sex hormone drugs. The BMA initially contradicted the Cass Review's conclusions and stuck with gender affirming care. In July 2024 the BMA’s council voted to oppose the implementation of the Cass Review.

The BMA said at that time that the recommendations by Dr. Hilary Cass were unsubstantiated. Leaders of the British Medical Association voted in favour of a motion calling for prompt access to gender-affirming medical interventions for under-18s, including sex hormones that block puberty.

The BMA announced it would carry out an evaluation of the Cass Review, raising concerns about weaknesses in the methodologies used in the review. It said that, in the meantime, implementation of the Cass Review should be paused. More than 1,400 doctors, 900 of whom are BMA members, signed an open letter calling for the BMA to drop its opposition to the Cass Review.

Some doctors resigned from the British Medical Association after being members for up to 50 years. The BMA’s membership base consists of 195,000 doctors.

Following criticism, the BMA council held a further vote in April 2026 to say it would approach its critique of the Cass Review neutrally. Dr. Hilary Cass said the BMA had no grounds on which to oppose her review.

She criticised the British Medical Association for its puzzling decision to oppose the findings of her review. Dr. Hilary Cass said the BMA had no evidence to back up its critique of her review. Dr. Hilary Cass said the BMA’s stance represented only a small minority of the medical profession.

She said the BMA’s critique was based on online sources mainly from the US. On Wednesday, May 6 2026, the BMA published its long-awaited critique of Cass’s work written by a task and finish group of 12 union members. Professor David Strain is the chair of the BMA’s board of science and lead author of the BMA’s critique of the Cass Review.

Professor David Strain told The Times that the baroness has been vindicated in the way she approached the data. He praised Dr. Cass’s methodological approach. " The BMA is holding on to one disagreement with the fallout from the Cass Review: doctors should still be able to prescribe puberty blockers, which were banned by the government.

U.S. medical association has supported the findings of the Cass Review. The American Society of Plastic Surgeons questioned some elements of gender affirming care in February 2026.