The Centre for Evidence-Based Medicine (CEBM Oxford University) researches, practices and disseminates evidence-based medicine in health care decision making. BBC's Panorama investigative programme asked the CEBM to review the research on puberty blockers. Professors Heneghan and Jefferson published a summary of their findings on the British Medical Journal's blog (emphasis added):
"An Archive of Diseases in Childhood letter referred to [puberty blocking] treatment as a momentous step in the dark. It set out three main concerns: 1) young people are left in a state of ‘developmental limbo’ without secondary sexual characteristics that might consolidate gender identity; 2) use is likely to threaten the maturation of the adolescent mind, and 3) puberty blockers are being used in the context of profound scientific ignorance."
"The development of these interventions should, therefore, occur in the context of research, and treatments for under 18 gender dysphoric children and adolescents remain largely experimental. There are a large number of unanswered questions that include the age at start, reversibility; adverse events, long term effects on mental health, quality of life, bone mineral density, osteoporosis in later life and cognition. We wonder whether off label use is appropriate and justified for drugs such as spironolactone which can cause substantial harms and even death. We are also ignorant of the long-term safety profiles of the different [cross-sex hormone] regimens. The current evidence base does not support informed decision making and safe practice in children."