Weakness of the evidence base
Three independent systematic reviews reach the same conclusion: the evidence for puberty blockers and cross-sex hormones in minors with gender dysphoria is of low quality.
Cass Review (UK, 2024)
After four years of research for the NHS, Hilary Cass concludes that the scientific basis for puberty blockers and cross-sex hormones in adolescents is "remarkably weak". NHS England withdraws routine use after publication. See cass.independent-review.uk.
NICE (UK, 2020-2022)
NICE evidence reviews judge studies on puberty blockers for gender dysphoria as having "very low certainty". No study meets the threshold for "moderate" or "high certainty" under GRADE methodology. See nice.org.uk.
SBU (Sweden, 2022)
The Swedish SBU evaluation classifies all treatment studies of puberty blockers and cross-sex hormones in minors as "low certainty of evidence". Sweden subsequently restricts treatment to research settings. See sbu.se/en.
What this means
Three independent evaluations, three identical conclusions. The Dutch Protocol — devised in Amsterdam, made internationally authoritative — rests on a far thinner basis than four decades of promotion suggested. Dutch clinics have not initiated a formal reassessment.