What American physicians have to say about new U.S. K. critique of transgender youth’s puberty-blockers

A long-anticipated — and contentious — national review of gender-affirming care for youth in England was released last week, resulting in headlines across the U.K. saying that gender medicine is “built on shaky foundations.”

The Cass Review, chaired by pediatrician Hilary Cass, was commissioned by England’s National Health Service (NHS) in 2020. 

Even before the final report was published, the review has led to significant changes for youth gender medicine in England, where the debate over transgender care has become increasingly heated, with complaints of both long waiting lists and medical treatments being too readily available to youth.

Last month, the Cass Review findings led to a ban on the prescription of puberty-suppressing hormones except for youth enrolled in clinical research.

That’s a move away from the standard of care supported by many international medical bodies, including the Canadian Pediatric Society (CPS), the American Academy of Pediatrics and World Professional Association for Transgender Health. Though several European countries including Sweden have also restricted access to puberty blockers and other medical treatments for youth.

The report cites a systematic review of evidence, commissioned as part of the Cass Review, which found “a lack of high-quality research” that puberty blockers can help young people with gender dysphoria.

While experts in the field say more studies should be done, Canadian doctors who spoke to CBC News disagree with the finding that there isn’t enough evidence puberty blockers can help.

“There actually is a lot of evidence, just not in the form of randomized clinical trials,” said Dr. Jake Donaldson, a family physician in Calgary who treats transgender patients, including prescribing puberty blockers and hormone therapy in some cases.

“That would be kind of like saying for a pregnant woman, since we lacked randomized clinical trials for the care of people in pregnancy, we’re not going to provide care for you.… It’s completely unethical.”

A person holds up a sign saying 'blockers are saving my kids life' as part of a protest in Ottawa.
Protesters hold signs up in Ottawa on Feb. 5, in response to Alberta premier Danielle Smith’s recent proposed youth transgender policies including a ban on puberty blockers for youth under 16. (Patrick Doyle/The Canadian Press)

What are puberty blockers?

When evaluating a drug or treatment, the question is always: how safe and effective is it? 

“Puberty blockers have been used for decades for precocious puberty,” or very early onset of puberty, said Dr. Sam Wong, president of the pediatrics section with the Alberta Medical Association.

“There are side effects with every medication, and I would talk [with patients and their families] about the side effects, but for the most part it’s a safe medication.”

Puberty blockers slow or pause the effects of hormones a young person’s body produces — for example, delaying the onset of a menstrual period or physical changes like breast growth, a lowered voice, or growth of the Adam’s apple. 

Their effects are considered reversible. When the medication stops, puberty resumes. 

The drugs are associated with lower bone density accumulation while someone is on them, and doctors can advise steps to counteract that, like weight-bearing exercise and using calcium or vitamin D as needed, according to the CPS position statement.

Their effectiveness in pausing puberty is not in dispute.

What is now banned by NHS England is the use of the medications specifically to treat “children and young people who have gender incongruence/gender dysphoria.” (Alberta’s plan to ban puberty blockers and hormone therapy in youth under 16 is also specific to gender affirmation.)

A smiling pediatric doctor in blue scrubs is seen in an unoccupied patient's room adorned with colourful stickers on the walls.
Dr. Sam Wong is president of the section of pediatrics with the Alberta Medical Association. (Submitted by Sam Wong)

Wong says when he speaks with a patient and their family, he discusses the bigger picture of gender-affirming care, including “the necessity of having some counselling and a thorough assessment before going forward with anything like medications.” He refers those who want to explore medication use to a specialist. 

“Sometimes those blockers allow the patient and their parents to have a couple more years without having to deal with the ramifications of puberty to decide if they want to move on with more gender-affirming care” such as hormone therapy.

Donaldson says, in the patients he treats, he’s seen dramatic improvement in the quality of life for transgender youth on puberty blockers.

“If a transgender youth is refused medication and is forced to go through a puberty that does not match their gender identity, that will put them in a body that will make them stand out as a transgender individual for the rest of their lives.”

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Scoring the evidence

The World Professional Association of Transgender Health (WPATH), in its influential guidelines, notes “the number of studies is still low” on gender-affirming care for young people, but there is a “slowly growing body of evidence supporting the effectiveness of early medical intervention.”

Numerous studies cited by WPATH, CPS and other medical groups suggest that access to puberty blockers helps transgender youth, and is associated with improved mental health and lower risk of suicidal thoughts and ideas

The difference between that characterization and the review published last week in the U.K. comes down to how the research done so far is viewed. 

The systematic review, published in the peer-reviewed journal Archives of Disease in Childhood, looked at 50 peer-reviewed papers published between 2006 and April 2022, and scored the strength of their evidence as low, moderate or high quality based on things like study design, outcomes and how many patients were involved. 

One was scored as high quality; 25 were moderate. Twenty-four of the papers, including the 2020 study on puberty blockers and suicidal ideation, which was based on a survey of 20,000 transgender adults, were excluded from the synthesis as “low quality.”

“No conclusions can be drawn about the impact on gender dysphoria, mental and psychosocial health or cognitive development,” the authors wrote.

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Dr. Tehseen Ladha, a pediatrician in Edmonton and assistant professor at the University of Alberta, says the review may be misleading and ignores the context of pediatric medicine — where there is often imperfect evidence. 

“That is the case in almost every sphere of medicine because the cost, time, feasibility and ethical ability to conduct what is considered a high-quality scientific trial, it is just not there,” she said.

Getting that research done can be even harder when it comes to marginalized populations like trans youth, she said. “They haven’t been thought of as priorities or important.”

Wong agrees there is often a lack of high-quality studies in pediatrics, saying 75 per cent of medications prescribed to children are used “off-label” because they were never tested on children. 

What does ‘low-quality evidence’ mean?

The gold-standard in determining effectiveness of a treatment is a randomized controlled trial where neither patient nor doctor know if they are receiving the treatment or the placebo.

But Wong says that’s not always feasible.

Beyond ethical concerns of doing such a trial on the mental health of young people with gender dysphoria, there would be no way to keep participants in the dark. 

“Within a few months, it’s obvious to the person that they’re on puberty blockers or they’re not on puberty blockers. So … they have feelings and they have impressions of what they should be going through,” Wong said. “So that’s going to influence the study itself.”

Protesters take part in the Trans Pride March in London, Britain, July 8, 2023.
People take part in the Trans Pride March in London on July 8, 2023. The political debate in the U.K. around transgender issues, especially youth gender care, has become increasingly heated in recent years. (Anna Gordon/Reuters)

Surveys and interviews are considered low-quality evidence in medicine, said Ladha, but that might be misleading to the general public. 

“Many people would see low-quality evidence and think well, that means this could harm our children. But that’s not what it means.”

Even something as routine as treating a kid’s ear infection with antibiotics or painkillers may not have robust evidence, notes Donaldson.

“That doesn’t mean we just every time we see an ear infection we turn around and walk the other way. Sometimes, an ear infection needs to be treated, sometimes it doesn’t.”

Ladha wondered if the review was “coming from a place of bias.”

“I think the framing of it really made it feel as though it was trying to create fear around gender-affirming care,” she said.

Donaldson called the systematic review paper and the broader Cass Review “politically motivated.” 

The Cass Review, while aiming to be an independent assessment, has been criticized as flawed and anti-trans by trans activists in the U.K., and was described as a product of the U.K.’s hostile environment for trans people in the International Journal of Transgender Health.

The review authors, based at York University in England, declined to comment on their research, though it was promoted in a media release by the British Medical Journal. The Cass Review also did not respond to a request from CBC News.

Protesters wave the LGBTQ flag at a rally.
Allies of the transgender community rallied in Edmonton’s Dr. Wilbert McIntyre Park in February after the premier said legislation on gender policies for children and youth would be coming this fall. (Charles Delisle/Radio-Canada)

Canadian groups support access 

Though the review’s findings are being used to restrict access to puberty blockers in the U.K., no Canadian medical organization that responded to CBC News said it would change advice here.

“As with all areas of medicine, new and emerging evidence is evaluated as it becomes available,” said the Canadian Pediatric Society in a statement. 

“Current evidence shows puberty blockers to be safe when used appropriately, and they remain an option to be considered within a wider view of the patient’s mental and psychosocial health.”

Children’s Healthcare Canada, which represents children’s hospitals, referred to its previous statement in support of evidence-based gender-affirming care for youth, saying: “Our position remains unchanged on the topic.”

Doctors say they’re used to advising patients about what is and isn’t known when it comes to a treatment, and helping them make an informed choice.

“None of this is being done in a vacuum,” said Donaldson.

“We have institutions that are set in place that are evidence based that are providing this care for individuals in a way that is following the guidelines to the best available evidence.”


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