LONDON — A clinical trial focused on puberty blockers for gender-questioning children will proceed with new age limits and safeguards. Dr. Hilary Cass stated that the trial aims to reduce harm and provide further clinical evidence.

The Pathways clinical trial, conducted by researchers at King's College London, is scheduled to begin recruitment in August, pending ongoing legal action. Researchers established age limits for participants: 11 for birth-registered female individuals and 12 for birth-registered male individuals. Medical regulators had previously proposed a minimum age of 14, which led to a pause in the trial in February after its initial announcement in November.

Dr. Cass stated that without such a trial, young people would continue to obtain drugs through unregulated channels. "I am absolutely convinced that more children will be harmed if we don't do the trial than if we do," she said. She added that the trial is essential to determine whether these drugs are helpful.

The trial will monitor participants' physical, social, and emotional well-being, including checks on bone density, brain function, and fertility. Cass noted that her 2024 review of gender medicine for children indicated weak evidence supporting the use of puberty blockers. The UK government implemented a UK-wide ban on the prescription of puberty blockers for individuals under 18 for gender care by the NHS or privately in 2024. Puberty blockers, also known as puberty suppressing hormones (PSH), are used to delay puberty.

Cass also stated that some of the risks associated with puberty blockers have been exaggerated. "Some of the hype about risks have been exaggerated in that we genuinely don't know if there are harms," she said. "It may be that if they were prescribed puberty blockers instead, that would give more time for the therapist to work with them and perhaps come to a different solution than a long-term life on medication." She cited instances of young individuals receiving testosterone at 11, describing it as irreversible. "Today we have young people turning up in the clinics on testosterone at 11, which we know is irreversible," Cass said. She added that testosterone should not be prescribed for children under 16 for gender treatment in the UK. "This group of young people and their families have been let down by NHS services for too long," she said.

Campaigners, including the Bayswater Support Group, are pursuing legal action against the trial, claiming it is unethical and that children cannot provide informed consent. A spokesperson said, "The trial risks causing irreversible harm to the participants and will not resolve the outstanding questions about puberty blockers." The Conservative party has also indicated a desire to force a vote in the House of Commons on the trial. Chay Brown, Healthcare Director of TransActual, welcomed the trial.