Debate › Science · Last reviewed 2026-05-16
Scientific criticism
Summary
Scientific criticism of the Dutch Protocol clusters around four points: (i) the absence of randomised or controlled studies, (ii) selective attrition and small sample sizes, (iii) limited follow-up duration and (iv) population shift between the original 1989–2005 cohort and contemporary referral patterns. The Cass Review (2024) summarises this criticism and uses it as a basis for its own recommendations. See also /studies/methodological-criticism/.
1. Central points
- No RCTs; only observational cohort studies — see /studies/replication-attempts/.
- Small sample sizes (n=55 in de Vries 2014) — see /studies/sample-size-and-attrition/.
- Short follow-up (1 year post-operatively) — see /protocol/follow-up/.
- Changed population: from early-onset, MtF-dominant to late-onset, FtM-dominant.
- Outcome measures heterogeneous between studies.
2. Response from the original team
De Vries, Cohen-Kettenis and colleagues have responded to the criticism in various publications — including in Pediatrics (2024) and Eur J Endocrinol (2024). Their position is that the Dutch Protocol constitutes an improvement over waiting or leaving untreated, and that further prospective study within clinical care is justified. See /debate/response-vumc-amsterdam-umc/.
3. Dutch critical voices
Within the Netherlands, criticism of the Dutch Protocol has so far concentrated in commentaries and publicly available analyses, not in official revision recommendations. A recurring point in these commentaries is that the Quality Standard Transgender Care (2017–2018) rests on the assumption that gender dysphoria in young people causes mental problems and that medical intervention reduces these problems — a causal assumption that, according to critics, has not been prospectively tested.1
The same commentary refers to a Finnish register study by Ruuska et al. (2026) reporting that the psychiatric care needs of treated adolescents increase over time rather than decrease. The authors of the Substack analysis Genderzorgen (10 April 2026) conclude that routine medical treatment outside research settings is ethically hard to defend, and refer to critical statements by psychologist Dorine Sellenraad (former VUmc, 2018) and parliamentary questions to Minister Hermans (VWS).2
Status of sources: the Substack publication is not peer-reviewed scientific literature and is — in line with the editorial methodology — cited as public commentary, not as a factual source. The underlying register study by Ruuska et al. (2026) will be tracked as soon as the peer-reviewed version is available.
See also
- People register — Biggs, Levine, Cass, de Vries.
- International comparison.
- Timeline.
- Methodological criticism — detailed dossier per study.
- Sample size and attrition — analysis of statistical power.
- Replication attempts — international replication attempts.
- Cass Review (2024) — UK systematic evaluation.
- SBU (2022) — Swedish evidence grading.
- Levine — critiques — overview of methodological objections.
- AUMC response — institutional response from Amsterdam UMC.
- FAQ · Glossary · For clinicians.
Footnotes
- Federation of Medical Specialists. Quality Standard Transgender Care — Somatic. 2018 (revised 2023) (translation by editors).
- Genderzorgen. Transgender care under scrutiny: an untested assumption as treatment protocol. Substack, 10 April 2026 (translation by editors). https://genderzorgen.substack.com/p/transgenderzorg-onder-de-loep