A High Court judge has dismissed a legal challenge against a clinical trial of puberty blockers for children, clearing the way for the study to proceed.

The decision was made on Friday, following a hearing earlier in the week.

Known as Pathways, the trial will enrol about 220 children experiencing persistent gender incongruence.

Half of the participants will begin puberty-suppressing medication immediately, while the other half will commence treatment a year later.

It comes after a review published in April 2024 by Baroness Cass, which concluded that there was insufficient evidence on the use of puberty blockers to enable clinicians and families to make fully informed decisions.

The legal action was brought by a campaign group and two people against the Health Research Authority (HRA) and the Department of Health and Social Care.

Their lawyers argued that there were significant concerns regarding the long-term physical and mental side effects on child participants, alleging a lack of proper safeguards and a flawed ethical approval process.

They had sought an injunction to delay the trial starting until their claim could be fully determined.

The claimants included the Bayswater Support Group, which consists of parents and guardians of trans or non-binary children and young adults, alongside psychotherapist James Esses and Keira Bell, who began taking puberty blockers at 16 before later “detransitioning”.

The HRA and the government opposed the bid to continue the legal action.

In a ruling on Friday, Mr Justice Chamberlain threw out the claim.

Reading a summary of his judgment, he said: “The trial was commissioned by NHS England and designed by its co-sponsors with conspicuous care, in consultation with other expert bodies.

“The participants will be children with persistent gender incongruence who are receiving treatment from specialist gender services.

“Each child will have been assessed over many months by specialist doctors. In each case, the treating team will have formed the opinion that the child has a reasonable prospect of receiving a clinical benefit from the treatment.

“There is a detailed process to ensure that the child assents, and a parent consents, to the treatment, having been fully informed of what it involves and of its potential outcomes.”

The judge continued that none of the grounds of challenge was “arguable with a realistic prospect of success”, and that the decision to approve the “pragmatic” trial was “quintessentially a question of judgment” for public health bodies.