Northern Ireland will be part of King’s College London’s Pathway trial of puberty blockers, which is set to examine the effects of puberty blockers on over 200 young participants over the course of four years.

As the BBC reports, a review of Northern Ireland’s gender services by Dr Hilary Cass stated that the area will be considered a research site for the puberty blocker trial, with Cass describing the need for engagement with the Pathway trial as “urgent”.

Cass was previously commissioned by the UK Government to evaluate the NHS youth gender services and recommended “extreme caution” in the provision of puberty blockers for those under the age of 18. However, multiple studies, including one published in November 2025, have found that gender-affirming hormone care, including puberty blockers, leads to a significant decline in suicidal tendencies for trans youth. Moreover, the Cass Review has been widely criticised for not including relevant research and failure to adhere to the scientific method.

The upcoming trial, which was announced following the UK’s ban on puberty blockers for under 18s, has been criticised by a number of trans healthcare advocacy groups, including EPATH, WPATH and USPATH. In a joint statement, the groups highlighted several ethical concerns in the trial’s design.

The first concern of the group is the study’s risk of coercion and how it may compromise the informed consent model.

“The proposed model links access to gender‑affirming care with participation in the study,” the statement reads. “This structure risks undermining voluntary informed consent by placing young people and their families in a position where declining participation may limit access to clinically indicated treatment.”

The three groups also warned of possible delays in access to gender-affirming care due to the trial’s design.

Their statement reads: “The study design includes delaying or restricting puberty‑blocking treatment for adolescents who meet clinical criteria. Such delays may prioritise research objectives over patient well‑being and contradict established clinical guidelines.”

Additionally, EPATH, WPATH and USPATH have outlined how there are ethical and clinical issues regarding the late initiation of puberty blockers, and urged that the research must not “compromise the health and safety of its participants”.

The groups have also called for the study to integrate trans youth, their families and community stakeholders into the research.