Mick Hartley

Marcus Evans was one of the original Tavistock whistle-blowers.

@rcpch_president helped put clinical governance back at the centre of clinical practice through her report. I am afraid the puberty blocker trial is a huge mistake. It risks taking us straight back to the problems that led to the closure of GIDS.
I was repeatedly told to trust…

— marcus evans (@marcuse99903226) June 21, 2026

I was repeatedly told to trust the research team. Yet the original study protocol proposed following children for only two years. That reveals a fundamental misunderstanding of the problem.

This is not like treating an infection and seeing whether the symptoms improve. Gender distress is a developmental issue that unfolds as a child moves through the physiological, psychological and social changes involved in growing up. If you intervene in that process, you inevitably affect the way the story unfolds. The consequences of such interventions are unlikely to be fully understood within a two-year follow-up period. Some of the most important questions only emerge later, as the individual reaches adulthood and reflects on relationships, fertility, family life, identity, and the opportunities that were opened or foreclosed along the way.

@SueEvansProtect and I have received countless letters from parents worried that their neurodiverse child has become caught up in a belief that transition will solve underlying difficulties. Many describe what @Hilary_Cass called diagnostic overshadowing, where every problem becomes understood through the lens of gender identity while other important factors are neglected.

The result is often a painful split between vulnerable children, worried parents and professionals committed to an affirmation approach. Families can find themselves pulled apart at precisely the moment they most need help to think together. Other families may support transition without fully understanding the potential harms, trade-offs and losses involved.

@WesselyS why are we not waiting for the long-term outcomes of the children already treated at GIDS before exposing another generation to the same intervention?

Psychiatry has a history of making well-intentioned interventions that later proved to be mistaken and, in some cases, damaging. That history should make us cautious. If puberty blockers alter the course of development, why are we proceeding with a new trial before we know what happened to the children who received them previously?