Cass Report Author Backs Puberty Blocker Trial to Prevent Harm

Dr. Hilary Cass, who authored an influential report on gender-affirming care for minors, expressed strong support for conducting a clinical trial on puberty blockers, arguing that conducting the research protects children from greater harm than proceeding without it.

"I am absolutely convinced that more children will be harmed if we don't do the trial than if we do," Cass said.

The trial proposal emerged from recommendations in Cass's report, which examined the medical practices and evidence surrounding gender-identity treatment in children. Her report prompted scrutiny of puberty blockers, medications that delay the physical changes of puberty and have become part of protocols for some transgender youth.

Proponents of the trial argue that better clinical data would help doctors make more informed decisions about when and how to use puberty blockers. Researchers and clinicians have noted that evidence gaps exist around the medications' long-term effects and their role in treatment pathways.

Cass framed the trial as a mechanism to reduce uncertainty for both patients and medical providers. By studying outcomes systematically, she suggested, clinicians could identify which young people benefit from the treatment and which face greater risks.

The proposal has drawn attention from multiple stakeholders in the debate over gender medicine for minors. Supporters of gender-affirming care have expressed concerns that research delays could restrict access to treatments that some youth and their families seek. Critics of such care have raised questions about the evidence base for current medical practices.

Cass did not specify which aspects of puberty blocker use the trial would examine or provide details on the study's design, scope, or timeline. She offered no comment on the broader controversy surrounding gender medicine protocols for children.