In a separate case (AB v CD and others), the High Court ruled that parents are allowed to give consent on behalf of their children to receive puberty blockers without having to gain a judge's approval.
In October 2019, a legal claim (a request for judicial review) was lodged against the NHS Gender Identity Development Service (GIDS) at its satellite site in Leeds.
[8] In the judgment delivered on 1 December 2020, which has now been overturned on appeal, the judges said that it was highly unlikely that a child aged 13 or under would be competent enough to give consent to puberty blockers, and that it was doubtful that 14 or 15 year olds could understand the long-term risks and consequences associated with them.
[14] Stonewall, Mermaids, and Gendered Intelligence conducted an online survey of over 200 parents whose children were being seen at Tavistock, on the waiting list, or considering a referall to gauge their responses to the ruling.
[15][16][17] The World Professional Association for Transgender Health and European, Asian, Australian, Aotorean, United States, and Canadian Professional Associations for Transgender Health released a statement in response to the ruling that "We are gravely concerned that the ruling will have a significantly adverse impact upon gender diverse youth and their families by imposing barriers to care that are costly, needlessly intimidating, and inherently discriminatory" and recommended "that capacity to consent is evaluated on a case-by-case basis by the treating clinician and not by a court of law.
[24] Alistair Robertson, a solicitor who advised the Tavistock and Portman NHS Foundation Trust, said going into the appeal "Our strategy had to be to focus the courts on the specific legal issues raised and away from the moral controversy around the treatment of children for gender dysphoria.
"[11] Following the appeal Helen Marshall, Chief Executive of Brook, one of the appellants against the original ruling, expressed delight with the appeal judgment and said "By confirming that clinicians are able to use their professional judgement to evaluate an individual young person's capacity to consent to the use of puberty blockers, today's judgment crucially upholds the principle of Gillick competence which underpins practice across health, social care and many other areas of work with young people.
Unlike proceedings for judicial review, that will provide a forum where the court is required to make factual findings, form judgments about clinical practice, and resolve disputes between experts.
[27] AB v CD and others is a separate case involving the Tavistock & Portman NHS Foundation Trust, on the related matter of whether parents can give legal consent to their child receiving puberty blockers.
"[28][29] In January 2025, it was reported that Keira Bell's lawyers had written to the Health Secretary, Wes Streeting, saying that unless he banned the use of cross-sex hormones for those under 18, they would challenge by judicial review his decision to allow their use by private clinics.