The Tavistock's Gender Identity Development Service (GIDS) was set up initially to provide talking therapies to young people who were questioning their gender identity. But in the last decade GIDS referred around 2000 children, some as young as nine, for medication to block their puberty. In the same period, the number of referrals exploded and the profile of the patients changed: from largely pre-pubescent boys to mostly adolescent girls, who were often contending with other difficulties. Was there enough clinical evidence to justify such profound medical interventions? This urgent, scrupulous and dramatic book explains how GIDS has been the site of a serious medical scandal, in which ideological concerns took priority over clinical practice. This edition contains an updated chapter.