Keira Bell transitioned to a male when she was a teenager, taking puberty blockers provided after consultations at the Tavistock, the UK's only gender-identity development service.

The 23-year-old says she should have been challenged more by medical staff over her decision.

She stopped taking cross-sex hormones last year.

The Tavistock said it always took a cautious approach to treatment.

The clinic added that it welcomed an examination of the evidence in this contentious area.