Reading Time: 4 minutes

Cass Review on gender transitioning revealed the harmful impact it is having on minors

Levi MinderhoudCanadian governments like to pride themselves on their commitment to evidence-based policies. From COVID-19 restrictions to climate policy and everything in between, evidence is king.

But there is one policy area in which evidence is conspicuously absent: medical gender transitioning for minors.

This lack of evidence was spectacularly brought to light in the UK’s recent Cass Review. Dr. Hilary Cass, a respected pediatrician, was appointed the chair of the independent review of Gender Identity Development Service (GIDS) for children and young people. The Review was spurred by widespread controversy over GIDS’ eagerness to prescribe puberty blockers and cross-sex hormones to minors to alleviate their gender dysphoria. Its findings and recommendations are striking.

The Review highlights how the UK’s gender identity services went about their work with an utter disregard for the scientific method and medical caution. The Gender Identity Development Service (GIDS) was established in 1989 and, for several decades, saw very few patients. Most were pre-pubescent boys with acute gender dysphoria.

Related Stories
Top pediatrician exposes damning truths behind gender-affirming care practices


There is no medical consensus on child gender transition


Alberta’s right to take a stand on youth gender treatment


GIDS usually provided counselling, not medical treatments. In 2011, following a novel approach to treating gender dysphoria pioneered in the Netherlands, GIDS decided to begin prescribing puberty blockers to children as a part of a research program. Essentially, the Gender Identity Development Service didn’t know whether prescribing puberty blockers to try to give children time to explore their gender identity would be better than just counselling, so they decided to do the rational thing to find out: start a medical trial.

However, they never finished this early intervention study. In fact, GIDS didn’t even collect the data they were supposed to. Instead, they ploughed ahead with prescribing puberty blockers and then cross-sex hormones to more and more children and adolescents without ever actually learning whether this was in their young patients’ best interest. In essence, they expanded what began as a medical trial in a research setting to thousands of children without looking back to see whether the treatment was working.

When this came to light, the National Health Service commissioned Dr. Hilary Cass to review the entire model of gender care in the UK. GIDS dug through its patient consultation notes and follow-up with patients to find the data needed to evaluate the Service’s medical transitioning program. When the results were finally published in 2021, they found that “there were no statistically significant changes reviewed in gender dysphoria or mental health outcome measures whilst on puberty blockers.”

But the Cass Review didn’t just want to see how children had fared under the care of GIDS. Cass commissioned six independent systematic reviews of all available evidence around the world of medical transitioning for minors to see if medical transitioning could ever reliably improve health and well-being. Systematic reviews are the highest quality academic evidence available because they collect all the studies done on an issue and combine, compare, and analyze their results. This allows researchers to learn from other time periods, other places, and other methods of study.

These systematic reviews all reached the same conclusion: there is no high-quality evidence to support medical transitioning for minors. To quote directly from the Cass Review, here is a sampling of the conclusions reached in the University of York’s systematic reviews:

  • “there is insufficient and/or inconsistent evidence about the effects of puberty suppression on psychological or psychosocial health” (p. 176);
  • “[there is] no evidence that puberty blockers improve body image or dysphoria, and very limited evidence for positive mental health outcomes” (p. 179); and
  • “the evidence for the indicated uses of puberty blockers and masculinising/feminising hormones in adolescents are unproven and benefits/harms are unknown” (p. 194).

As a result, the overview of the Review’s key findings states that “for most young people, a medical pathway will not be the best way to manage their gender-related distress.” Puberty blockers and cross-sex hormones should not be offered to minors under the age of 16. Even for adolescents over age 16, the Review recommends “extreme caution.”

Simply put, medical transitioning is generally the wrong treatment for gender dysphoria in minors. One Canadian province – Alberta – has recognized this fact and pledged to greatly limit medical transitioning for minors.

Will other Canadian provinces finally examine the evidence and follow suit?

Levi Minderhoud is a policy analyst for the Association for Reformed Political Action (ARPA) Canada.

For interview requests, click here.


The opinions expressed by our columnists and contributors are theirs alone and do not inherently or expressly reflect the views of our publication.

© Troy Media
Troy Media is an editorial content provider to media outlets and its own hosted community news outlets across Canada.