Screenshot from the 2023 oral history interview with Prof. Dr. Peggy Cohen-Kettenis (Archive for Dutch Behavioral History / Maanvis YouTube channel).
Published on July, 13 2026
by Hermes Postma
Original: Inspecting Gender – Peggy Cohen-Kettenis: The Dutch Architect of a Global Medical Scandal
From Utrecht to the World: How One Psychologist Turned a Care Model into Self-Destructive Medical Consumerism.
While John Money has long been the symbol of the failures within gender ideology, a far more direct and influential figure has remained remarkably out of the spotlight: Peggy Cohen-Kettenis. She was the central Dutch master builder who, step by step, laid the foundation for what ultimately became an international medical scandal.
Peggy’s career was launched under Louis Gooren, the VU professor who aggressively medicalized transsexuality and served as one of her most important early mentors. In 1991, the book by her PhD student Kuiper appeared, describing the early studies by Cohen-Kettenis and Kuiper on transition care. Among 105 men, there were 11 deaths (and a 12th death appeared in a newspaper shortly after). Yet the conclusion presented the care as beneficial. Most patients said they were satisfied, so: success. This while a large part of the group (around 70%) was lost to follow-up — a classic way to obscure poor outcomes. The group of non-respondents were mainly men who had undergone genital surgery, while most women still had intact genitalia.
This pattern characterises her entire career. Even in her early follow-up studies (late 1980s), she presented the results positively, while the hard data (high mortality, limited follow-up) painted a much bleaker picture. Positive self-reporting consistently outweighed objective outcomes such as death.
The Utrecht Scale (UGDS)
It really took off in 1995 with an apparently simple tool: the Utrecht Gender Dysphoria Scale (UGDS). Cohen-Kettenis presented this short questionnaire as a reliable psychometric instrument. The items are shocking: “I hate menstruating because it makes me feel like a girl,” “I like to behave sexually as a girl,” “I hate urinating while standing,” and even “It would be better not to live than to live as a boy.”
In practice, this list replaced proper differential diagnosis. Comorbidities such as autism, trauma, depression, and insecurity resulting from homosexuality were increasingly dismissed under the label of “minority stress.” The hetero anamnesis and second opinions faded into the background. Whoever gave the right answers quickly received the green light for medical treatment. Every patient automatically scored positively. Self-reported “gender identity” became the deciding factor, rather than careful psychiatric assessment.
The Dutch protocol is being exported
From that moment on, the path was clear for the next major project. The Utrecht clinic moved to Amsterdam, and there Cohen-Kettenis developed the Dutch Protocol: puberty blockers from Tanner stage 2, followed by cross-sex hormones and surgery. She sold it as “reversible” and a way to “buy time for exploration.” For most young people, it turned out to be a one-way street. In the first major study on this protocol (de Vries et al., 2011), the first 70 young people who received puberty blockers were followed. Strikingly: only one person turned out to be heterosexual. This is exactly the pattern long known in early-onset gender dysphoria — many of these children would probably have grown up to be gay or lesbian without medical intervention. The mechanism of transing the gay away is impossible to ignore in this cohort.
Her influence was not limited to the Netherlands. She co-authored the Endocrine Society guidelines of 2009 and 2017, multiple versions of the WPATH Standards of Care (SOC 5, 6, and 7), and influenced the WHO ICD-11. Through this network, she exported the Dutch model worldwide. At home, she cleverly played the system: she presented the international consensus as an independent, unanimous truth — even though she herself was one of the main authors of those guidelines. In this way, the NZa, IGJ, and the Ministry of Health were drawn into a circle of self-affirmation.
The pinnacle of her institutional power came with the DSM-5. As chair of the subworkgroup on Gender Identity Disorders, Cohen-Kettenis was co-responsible for the shift from Gender Identity Disorder to Gender Dysphoria. What had been a disorder was rewritten as a natural identity. This opened the floodgates for an explosive rise in referrals, especially among teenage girls.
Throughout it all, the ideological thread remained visible. In a 2023 interview, she still proudly recounts how John Money called her “the bravest person in the room” after the first puberty blocker cases. Twenty years after Money had been exposed as a child abuser and fraud, she praised him as “the great sexologist.”
The hour of reckoning
Recently, the American FTC (June 2026), together with several states, filed a major complaint against WPATH. It explicitly points to the Dutch origin: the Utrecht clinic of Cohen-Kettenis and her boss Louis Gooren. The Dutch Protocol is described as the root of the entire edifice — built on a single case study, financed by the pharmaceutical industry, and without solid long-term research. The complaint accuses WPATH of systematic deception regarding reversibility, suicide prevention, and scientific substantiation.
The circle is complete. From a Utrecht questionnaire to international guidelines, and ultimately to lawsuits in America. In the Netherlands itself, criticism remains remarkably absent, and Cohen-Kettenis stays out of the spotlight.
It is time for Peggy Cohen-Kettenis to take full accountability for the tens of thousands of young people who, through her model, embarked on a medical path with often irreversible consequences. No more denial or evasion. Only openness, independent research, and a fundamental change of course.