Puberty Blockers

How many children are being treated with puberty blockers in Canada?

The numbers of children being treated with puberty blockers in Canada is unknown, but given that the rise of gender dysphoria in Canadian is similar to that in other western countries like the US and UK, it is expected to be growing at rates of 1000’s of % over the past 5-10 years and would now represent thousands of children across the country. 

Puberty blockers and other hormones are being offered to children at the first visit to a gender clinic in 62% of cases, according to recent research conducted by the Trans Youth Can team. Many gender clinics have adopted the policy of offering puberty blockers or cross-sex hormones at a first visit. This is in line with the move to eliminate the need for mental health assessments.

Please note: we’ve had some pushback from Canadians writing to us to say that these numbers can’t be correct because of a belief system many of us have that our healthcare system would approach this issue with more caution. Unfortunately, this position does not stand up to scrutiny or testing. For example, Radio-Canada wanted to see how quickly a 14-year-old girl would be able to obtain a testosterone prescription. It took their undercover 14-year-old less than 10 minutes to obtain the script.

Radio-Canada “Are puberty blockers prescribed too quickly to young people”

If you were under the assumption that gender clinics in Canada are being cautious please read the rest of this page with a more open mind. We know it’s difficult to accept that things have changed so drastically in Canada.

62% of children receive Puberty Blockers or Hormones at their first visit to a Gender Clinic

After Premier Danielle Smith announced her new policies, CGR received an influx of questions from Canadians who seemed in disbelief about this statistic. Therefore, we’re adding more information from the study and we also attest that the 2/3 statistic is in line with anecdotal reports we’ve heard from dozens of parents. Yes, puberty blockers or cross-sex hormones are being offered to children and teens at their FIRST visit to a gender clinic. Here is one account from a parent of a now desisted teenaged girl who was offered puberty blockers at her first appointment at the Sick Kids gender clinic.

The study methodology recruitment parameters identify that these youth have been referred for hormones. This is the way that children and teens are able to access gender clinics in Canada. You can’t simply walk into one of Canada’s Children’s Hospital gender clinics without a referral. There is also more information in the “Generalizability” section of the study. It states: “The study population is likely representative of youth <16 years of age referred for hormonal suppression or hormone therapy to specialized medical clinics in Canada. We included all major clinics providing such care during the study period. Although recruitment period varied by clinic, we weighted results to remove this potential bias. Some community clinics, family doctors, and general pediatricians have begun providing hormonal suppression for younger youth, including those in rural areas, often in consultation with subspecialists; such youth are not represented in this study”.

Under “Clinic Visit Outcomes” – the description just above Table 4, it states “Of 46 participants not prescribed hormones at this visit, physician’s reason was included in 36 records. The most common reason was the clinic protocol of not prescribing at first visit.” (emphasis ours) The paragraph here goes on to detail other reasons youth do not receive a prescription at their first visit to a gender clinic in Canada; these can include “fear of needles”.

Are puberty blockers reversible? 

The “reversibility” claims were made based on the usage of puberty blockers to halt “precocious puberty” – puberty in children as young as 8 years old. In these cases, gender dysphoria is not a factor.

What has been found in the usage of puberty blockers as part of “gender affirming care” is that the vast majority of children who begin treatment with puberty blockers move on to cross-sex hormones as well. In the UK, the finding from clinical data was that over 95% of children treated with puberty blockers also subsequently received cross-sex hormones.

The strength of this relationship is extremely unusual for medical practice.  Since most children who begin puberty blockers move on to cross-sex hormonal treatment, which have irreversible effects, it is difficult to pull apart the effects of puberty blockers alone. Research suggests that puberty blockers, even if followed by cross sex hormones decreases bone density and may have a negative impact on cognitive function. Most clinicians now acknowledge that puberty blockers are not reversible and many believe that being put on a puberty blocker concretizes a trans identity, putting them on a life-long medical pathway.

Contrast this to the previous “watchful waiting” model in which children were given time and space to mature, the vast majority (68-98%) had their gender dysphoria resolve and they aligned with their biological sex by early adulthood, with most growing up to be LGB. 

Clinicians who use puberty blockers as a first line of treatment (as most do in Canada today) are promoting a belief to their young patients that they are doing something that is good for them. There is a significant amount of trust among Canadians that our medical professionals would only offer or recommend such invasive treatments if they were sure they were in a young person’s best interest.

What can we believe about the safety of puberty blockers?

The Society for Evidence-based Gender Medicine recently reviewed the current state of information on puberty blockers. They state:

“While puberty blockers used to halt early (precocious) puberty have been shown to be reversible, no such studies exist for puberty blockers administered to stop normally timed puberty.”

Society for Evidence-based Gender Medicine

The Cass review, currently being conducted in the UK to evaluate how to best care for gender-dysphoric youth, made this noteworthy statement in its interim report:

it is important that it is not assumed that outcomes for, and side effects in, children treated for precocious puberty will necessarily be the same in children or young people with gender dysphoria.”

– UK Cass Review

Puberty blockers appear to be psychologically irreversible (since over 95% of all treated youth proceed to cross-sex hormones). There is also clear evidence that puberty blockers may harm bone development, may permanently alter the brain, and it is not yet known how they affect other vital organs, all of which undergo significant changes during uninterrupted puberty. The UK’s National Health Service recently updated its guidance, removing statements about the reversibility of puberty blockers. Instead, the NHS now says:

Little is known about the long-term side effects of hormone or puberty blockers in children with gender dysphoria.” and “it is not known what the psychological effects may be”.

UK National Health Service update to guidance

When did Canada first begin using puberty blockers? 

Usage of puberty blockers in Canada began in 2005, less than 20 years ago. The CAMH GIDS clinic in Toronto was the first clinic to introduce them, under strict cautionary principles and after much assessment and reflection with their young clients to try to determine whether they would be in a young person’s long-term best interest. Parents were an integral part of this decision-making process.

The founder of the CAMH GIDS clinic, Dr Susan Bradley, told us in an interview that the Canadian clinic started using puberty blockers with children who had a long history of gender dysphoria. A young person needed to be 16 before they were even offered puberty blockers. She said that the clinicians really had nothing but a “gut feeling” to go on and that they had adopted the usage of puberty blockers based on the Dutch protocol, which presented puberty blockers as reversible.   

Soon after, medical societies started to produce guidance for the usage of puberty blockers based on the initial Dutch study of 55 young people (this cohort all presented with persistent and consistent early-onset childhood gender dysphoria, unlike many young people seeking gender transition today). Societies such as the American Academy of Pediatrics and the Endocrine Society endorsed this protocol on the belief that these kids were suicidal and that these interventions were life-saving. At the time, they also believed that puberty blockers were a “pause button” and fully reversible.

Are puberty blockers approved for use to treat gender dysphoria in minors? 

No. While puberty blocking drugs such as Lupron have been approved and used for precocious puberty (when a child begins to show secondary sex characteristics very early), they have never been approved for treating gender dysphoria in children at a normal age of sexual development, and for a much longer period of time. The usage of puberty blockers for gender dysphoria is “off-label”, meaning that physicians prescribe them based on a hope that they can be effective and that the risks will not outweigh the benefits. There have been no good quality studies of the effects of this treatment. It is highly unlikely that Canadian clinicians are systematically collecting data on the effects of these medications. Such was the case at the Gender Identity Development Services at the Tavistock, the largest gender clinic in the UK, which was ordered to be shut down following numerous issues with an unproven treatment protocol and inadequate collection of data and patient follow-up. 

Approval for usage would require that studies are undertaken to ensure the drugs provide the expected benefits and that the level of risk and side-effects are understood and acceptable. There is a growing body of evidence that the practice of using puberty blockers may be creating harms that are not acceptable. 

What are the side effects of puberty blockers? 

Known side effects of puberty blockers include:



•Mental illness (depression, suicidality, aggression)


•Poor bone growth/Short stature

•Chronic pain

•Potential negative effects on brain development

•Lack of penile length/scrotal tissue for future vaginoplasty

95-98% of children who are treated with puberty blockers go onto cross-sex hormones.

Recently, the British Journal of Medicine published an excellent summary of the current state of research in this area. The weak evidence, the article states: “doesn’t just mean something esoteric about study design, it means there’s uncertainty about whether the long term benefits outweigh the harms”. Canadian health research methods expert, Gordon Guyatt of McMaster University, who co-developed GRADE, a systematic approach to rate the quality and certainty of research evidence, is quoted heavily in this piece. 

How are vulnerable children being protected from harm?

Unfortunately, it’s not clear that vulnerable children are being protected from harm. There seems to be a growing belief system that medical gender transition is simply a reversible “gender journey” (to use a term quoted to us by Sick Kids Hospital). Is it facile to think of treatments that can have permanent changes on a young person’s physical, cognitive and emotional health as a gender journey?

The term “assessment” has been hi-jacked to mean different things. Clinicians within Canadian children’s hospital gender clinics have been quoted in the media saying that “comprehensive assessments” are done before children are started on invasive medical treatments, but that is clearly not the case if puberty blockers are often being initiated at the first visit. The London Gender Pathways Service even created a “consent” form for family physicians to use to initiate puberty blockers BEFORE a first visit to the gender clinic.

A typical assessment today includes a checklist of items that includes questions about medical history. However, clinicians are not given direction about what to do with the information gathered on the checklist. If, for example, a child is autistic, there are no standardized pathways or assessments to determine whether this child has adopted rigid thinking about gender while there are other factors at play. Youth on the ASD spectrum typically have difficulty with self-regulation and don’t feel like they “fit in”, which can lead to depression, anxiety or suicidal thoughts. When such a youth, latches on to the idea that their distress is because they are transgender, their black and white thinking makes it very difficult for them to think more abstractly about sex and gender.  Unfortunately,  when gender becomes a focal point, all else is ignored, not only by the youth, but also by affirming school staff, therapists and physicians.

Canadian autistic children are being put on puberty blockers, cross-sex hormones and have undergone surgeries without being provided appropriate support to understand and manage their mental health issues (and explore how their gender-related distress may be entangled with these other issues). This is also the case for young people who are gay and may be having difficulty understanding or accepting their sexual orientation, those who have suffered a history of trauma such as a sexual assault and for an unexplained and disproportionate number of children living in foster care and identifying as First Nations.  

Perhaps rather than asking whether puberty blockers are reversible, we should be asking some hard questions:

  • Does the initiation of puberty blockers encourage children to undergo unnecessary medical treatments?
  • Does the initiation of puberty blockers hinder the exploration and treatment of underlying mental health issues?
  • Does the initiation of puberty blockers hinder the resolution of gender dysphoria?
  • What evidence is there that puberty blockers support long-term mental and physical well-being?

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