International › Spread · Last reviewed 2026-05-16

Spread of the Dutch Protocol

Summary

The international spread of the Dutch Protocol came in three main waves: (1) endorsement by the Endocrine Society (2009, revised in 2017), (2) integration into the WPATH Standards of Care (SOC-7, 2012), and (3) translation into national guidelines and clinical service models in more than thirty countries between 2010 and 2020. Tavistock GIDS in London was the largest international clinic to adopt the model.

1. Key dates

Year	Event
2006	Delemarre & Cohen-Kettenis publish protocol
2009	Endocrine Society Clinical Practice Guideline
2011	Tavistock GIDS starts early-intervention pilot
2012	WPATH SOC-7
2014	Publication of de Vries cohort
2017	Endocrine Society revision
2018	Quality Standard Transgender Care (NL)
2022	WPATH SOC-8

2. Why did it spread so quickly?

Several factors are mentioned in the literature:

The Dutch Protocol was for a long time the only explicitly published phased model for adolescent gender dysphoria.
The authors published positive outcomes in influential journals (Pediatrics, J Sex Med).
International endocrinology and transgender organisations adopted it in their guidelines.
Strong growth of referrals from around 2010 put pressure on clinics to have a workable protocol.

3. Deviation in implementation

The Cass Review (2024) and various authors (Levine 2022, Biggs 2023) note that the protocol in international application deviated from the Dutch original on key points: less strict inclusion criteria, shorter diagnostic phase, and higher ages at first referral than in the original cohort.¹

Critical note

The rapid international spread happened on the basis of two Dutch cohort publications (2011, 2014) with a total n of 70/55, without prior replication. Biggs (2023) calls this "policy diffusion without evidence diffusion": guidelines and clinics adopted the Dutch approach before independent research could confirm the outcomes. When replications later did follow (Costa 2015, Carmichael 2021), they did not confirm the Dutch outcomes — but by then the protocol was already standardised.²