Government’s puberty blockers ban treated uncertainty as disqualifying - researcher
The Government restricted the initiation of puberty blockers for people under 18. Photo / 123RF
A new study concludes that the Government used uncertainty about puberty blockers to bypass routine governance tools and restrict young people from initiating treatment.
The report, by Dylan A. Mordaunt, published in the New Zealand Medical Journal today, analysed the core documents structuring the Government’s 2025 decision to restrict the initiation of puberty blockers for people under 18.
Existing patients and other indications were not targeted in the changes, which affected off-label prescribing.
Puberty blockers are medicines that pause unwanted physical changes in young people with gender dysphoria, or the psychological distress that can arise from feeling their gender does not match the sex they were assigned at birth.
The paper notes that in routine medical practice, doctors can prescribe medicines “off label”, meaning outside their formally approved uses, particularly when treating children.
According to the study, uncertainty about medicines is usually managed through clinical guidance, monitoring and professional oversight rather than categorical restrictions.
However, the study says the Government treated uncertainty as “uniquely disqualifying” in the case of puberty blockers.
Mordaunt analysed nearly 70 policy documents and related releases connected to the Government’s decision.
He argues that those documents do not show evidence of clinical failures in New Zealand, confirmed harm to patients or plans for local trials that would justify the restriction.
Instead, the paper describes the decision to restrict puberty blockers for under-18s as an example of what it calls “regulatory exceptionalism”.
The study says New Zealand’s announcement materials “explicitly invoked uncertainty and the prospect of future evidence generation in the UK” when justifying the restriction.
Court records cited in the paper suggested the trials could take “five to six years” to produce results.
The paper says uncertainty about puberty blockers could have been handled differently.
Instead of restricting the treatment through regulation, it suggests stronger clinical oversight, such as clearer prescribing thresholds, monitoring systems and regular review.
Mordaunt also argues that the way the restriction was introduced, through regulation under the Medicines Act, may make it harder to change as new evidence emerges.
“Delegated legislation … tends to be binary and slower to recalibrate once made,” the paper says.
The study also questions how the restriction will be reviewed in the future, including what new evidence would be needed to change the policy and who would need to provide it.
The paper concludes that the Government applied a higher evidentiary and governance standard than elsewhere in paediatrics, and routed a “contested clinical issue” through an executive regulation pathway.