The Netherlands: Amsterdam UMC and the Dutch reassessment

How has the Netherlands responded to criticism of its own protocol, and what has the Dutch health ministry decided?

The Netherlands matters because the “Dutch protocol” became the best-known model for paediatric medical transition internationally. It was developed at the Amsterdam gender clinic, formerly VUmc and now Amsterdam UMC, around a highly selected group of adolescents with persistent gender dysphoria, intensive assessment and family support. The model combined psychological assessment, puberty suppression after the onset of puberty, cross-sex hormones in later adolescence, and, historically, surgery in adulthood.

Background

The Netherlands matters because the “Dutch protocol” became the best-known model for paediatric medical transition internationally. It was developed at the Amsterdam gender clinic, formerly VUmc and now Amsterdam UMC, around a highly selected group of adolescents with persistent gender dysphoria, intensive assessment and family support. The model combined psychological assessment, puberty suppression after the onset of puberty, cross-sex hormones in later adolescence, and, historically, surgery in adulthood.

The early Amsterdam studies were influential. The best-known follow-up, involving 55 selected young adults who had proceeded through puberty suppression, hormones and surgery, reported improved psychological functioning and reduced dysphoria after treatment (de Vries et al., 2014). A later Amsterdam cohort study found that 704 of 720 people, or 98%, who began puberty suppression and subsequent hormones in adolescence were still using hormones at follow-up (van der Loos et al., 2022). Continuation, however, is not identical to a finding of benefit, absence of regret, or proof that the treatment was appropriate for every participant.

The patient population changed markedly. The Health Council reported that Dutch referrals to specialist and mental-health providers rose from 1,179 in 2020 to 2,772 in 2022. It also recorded a higher proportion of females, older adolescent presentations, non-binary identities and co-occurring psychosocial problems, including autism, mood problems and ADHD. This matters because the original evidence base was built on a narrower clinical population than the one now seeking care (Health Council of the Netherlands, 2026).

What the documents say

The 2024 evaluation of the quality standard

Before the Cass Review was published, the Dutch system had already begun a formal reassessment. The Ministry of Health commissioned ZonMw to facilitate an evaluation of the Kwaliteitsstandaard Transgenderzorg – Somatisch. The Kennisinstituut of the Federation of Medical Specialists completed its report on 28 February 2024; the government sent it to parliament on 5 April 2024.

The evaluation did not recommend abandoning the standard. It did, however, conclude that parts were no longer fully current and that recommendations in several modules should be reconsidered against the latest science and clinical practice. It called for a broader and stronger scientific basis, better organisation between primary, secondary and tertiary care, more attention to psychosocial support and aftercare, and care better tailored to a more diverse patient population (KIMS Evaluation, 2024). A multidisciplinary revision process was then started.

This is significant: the Dutch response was not to declare its protocol settled science. It accepted that the standard required revision. But it placed that work within ordinary professional guideline development rather than imposing an immediate ministerial restriction on puberty blockers or hormones.

Amsterdam UMC’s response to Cass

Following the publication of the Cass Review on 10 April 2024, Amsterdam UMC accepted several of its service-design recommendations: reducing waiting lists, distributing expertise, providing multidisciplinary care and expanding research. It said that these features had long been central to Dutch practice.

Amsterdam UMC nevertheless disputed Cass’s conclusion that there was insufficient scientific evidence for puberty blockers. It argued that randomised placebo-controlled trials would be ethically impracticable in this setting, and maintained that existing Dutch and international follow-up studies showed favourable outcomes in psychological wellbeing and quality of life. It supported continued monitoring of long-term outcomes and stated that puberty blockers were prescribed only to a limited group within multidisciplinary academic networks (Amsterdam UMC, 2024).

The disagreement is therefore precise. Cass did not say that randomised trials were the only acceptable evidence; it concluded that the available evidence was too weak to establish the safety and effectiveness of the interventions with confidence, and advised that puberty blockers should be available only in research settings. Amsterdam UMC accepted the need for better evidence but rejected research-only provision as ethically wrong where clinicians judged treatment necessary (Cass Review, 2024; Amsterdam UMC, 2024).

The Health Council’s 2026 advice

The decisive national reassessment began when the Ministry asked the Health Council on 13 May 2024 to examine three questions: whether the Dutch somatic-care standard fitted the legal framework; what was known about physical and mental outcomes; and what was known about stopping treatment, regret and detransition. It was also asked to compare the Netherlands with other European countries.

The Health Council’s report of 30 June 2026 found that the Dutch pathway fitted the relevant legal framework, including the Medical Treatment Contracts Act and the Healthcare Quality, Complaints and Disputes Act. Its legal assessment, however, was based on the guidelines and stated design of care, not an audit of how every clinic applies them in practice (Health Council of the Netherlands, 2026).

The Council concluded that hormones achieve their intended physical effects and that there were indications of some mental-health improvement. Yet it also described the evidence as generally low quality, noted the lack of long-term data, and identified insufficient evidence on cognition and fertility. It acknowledged that short follow-up and substantial loss of participants make definitive conclusions about regret impossible. It further stated that some people who stop treatment or regret it may not report this to their original providers and therefore may be missing from clinic-based studies.

Its recommendations were not trivial. It called for more gender-questioning children to be supported in primary care and mainstream mental-health services rather than rapidly medicalised through referral; fuller documentation of diagnostic assessment and indication-setting; explicit assessment of a young person’s decision-making capacity; standardised national monitoring; longer follow-up into adulthood; and specific research and support for those who stop, regret or detransition.

The positions

Amsterdam UMC and supportive professional bodies argue that the Dutch model is already cautious: assessment is extensive, parents are involved, co-existing problems should be addressed, and only a minority of referred young people receive medical treatment. They argue that uncertainty is inherent in paediatric medicine and does not justify withholding treatment where distress may also carry risks. The Health Council broadly accepted this framing in 2026, while asking for clearer safeguards and better research.

Critical clinicians, researchers, parents and detransitioners make a different argument. They point out that the evidence underpinning medical transition is largely observational, often derives from specialist clinics, lacks untreated comparison groups and does not adequately represent the newer, predominantly female and more clinically complex referral population. They argue that uncertainty over fertility, cognitive effects, long-term physical outcomes and regret should lead to greater precaution, as in Finland, Sweden and England.

The Cass Review represents the clearest institutional version of the precautionary position. It argued for a far stronger evidence base and for puberty blockers to be offered only under research protocols. The Dutch Health Council did not adopt that recommendation. Instead, it judged the existing Dutch pathway sufficiently careful to continue while its evidence base is strengthened.

Interpretation

Beyond Gender’s reading is that the Netherlands has responded to criticism by commissioning a serious reassessment, acknowledging evidential weaknesses and promising better safeguards, while declining to interrupt the medical pathway that generated the original evidence. That is a partial correction, not a fundamental change of direction.

The central tension in the 2026 Health Council advice is hard to avoid. It says the evidence is generally low quality; long-term outcomes, cognition and fertility remain uncertain; regret cannot be reliably quantified; and the current population differs materially from the historic Dutch cohorts. Yet it concludes that these uncertainties do not justify a change in the organisation of care. This is a policy and ethical judgement, not a purely scientific deduction.

The Ministry’s actual decision is narrower than headlines may suggest. It decided in May 2024 to seek independent advice. On 30 June 2026 it transmitted that advice to parliament, said it would consult interested parties, and promised a substantive cabinet response before the autumn recess. Its letter did not announce a pause, a ban, research-only provision or a new clinical eligibility rule. As at 11 September 2026, the promised policy response had not been published.

Open questions

Will the government’s forthcoming response require concrete changes to eligibility, assessment, capacity testing, fertility counselling and data collection, or merely endorse a future revision of the quality standard? The answer matters because the Health Council’s legal conclusion concerned the model on paper rather than a systematic inspection of clinical practice.

Can the Netherlands establish national, mandatory and long-term follow-up that does not depend on patients returning to the same gender clinic? Such monitoring would need to record physical health, mental health, fertility outcomes, discontinuation, regret and detransition into adulthood.

Most importantly, will future studies distinguish between the original early-onset, carefully selected Amsterdam cohort and today’s much broader referral population? Until they do, claims that the historic Dutch results validate present-day treatment for all groups remain an extrapolation rather than a demonstrated conclusion.

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