Established in 1989, Gender Identity Development Services of Tavistock Clinic had to close down in April 2022. Their services prescribed puberty blockers to more than 1000 children, many under 16 years of age, questioning their gender identity. A book written by Hannah Barnes, examines how the clinic shifted from examining distressed teenagers, using therapy to work out how best to help them, to becoming a conveyor belt to puberty blockers, cross-sex hormones and drastic surgery. The book is a cautionary tale about the dangers of institutions putting profit over patient welfare and the importance of collecting and scrutinizing evidence. It also exposes the nervousness of clinicians in speaking up, despite growing concerns about the clinic’s direction, and the wilful failure to safeguard the wellbeing of children seeking help.