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Systematic reviews

The gold standard in medicine. These systematic reviews looked at all of the scientific literature regarding sex-rejecting drugs and procedures for children.

Reviews in the U.S., Canada, England, Sweden, and Finland all came to the same conclusion.

The evidence in support of child transition is very weak or non-existent.

There is no justification for causing serious, lifelong physical harm in kids.

HHS Evidence Review: Treatment for Pediatric Gender Dysphoria (November 2025)

Provide accurate information on the current evidence for treating gender dysphoria in children and adolescents, assess the state of medical practice in the U.S., and explore the ethical issues related to these treatments.

A lack of evidence demonstrating medical and surgical treatments for gender dysphoria in children improve mental health or reduce gender dysphoria effectively.
Puberty blockers and hormones of the opposite sex can cause significant harms, such as infertility, making the risk/benefit balance unfavorable.
Weak evidence calls for cautious guidelines and policies, emphasizing ongoing evaluation and improved data collection.
Patients and families are not provided clear information on the benefits, risks, and uncertainties of treatments due to inadequate informed consent.

Read the summary View the study

The Cass Review: Study of Adolescent Gender Dysphoria Treatment (UK)

Independent Review of Gender Identity Services for Children and Young People to provide recommendations on issues related to the delivery of these services.

Early studies (2015–2016) found no benefits from puberty blockers, with 2020 results confirming no positive outcomes.
Despite this, puberty blockers became routine in 2014, used on a wider patient group not meeting original research criteria.
Using a treatment with unclear benefits without further review significantly deviates from standard medical practice.
Cass is backed by University of York reviews of all the studies and by England’s treatment-advice body (NICE) 2020 reviews of puberty blockers (GnRH analogues) and hormones of the opposite sex. Those papers are not listed as separate Facts cards.

Read the summary View the study York systematic reviews — Archives of Disease in Childhood series Cass Review — NICE evidence reviews (2020)

Canada — McMaster HEI systematic reviews cover

Canada — McMaster HEI systematic reviews: Puberty blockers, hormones, and double mastectomy in youth — very weak evidence (2025)

McMaster’s evidence institute (HEI) published systematic reviews of sex-rejecting procedures, grading how sure we can be about the results (GRADE). The HEI department page does not list the papers one by one; the published reviews are the puberty-blocker and hormone reviews and the mastectomy review. They are not a Canadian government ban.

Puberty blockers: 10 studies. Evidence comparing treated and untreated youth on everyday function and depression was very weak. Before-and-after evidence on gender dysphoria, function, depression, and bone strength was also very weak. The authors report considerable uncertainty about effects.
Hormones of the opposite sex under 26: 24 studies. Most comparison evidence was very weak on dysphoria, function, and depression. One comparison study reported somewhat lower odds of depression, still at low certainty. The authors say they cannot rule out benefit or harm.
Double mastectomy under 26: 39 studies. Comparison and before-and-after evidence ranged from low to very weak, including very weak evidence on gender dysphoria, everyday function, and suicide attempts.
The HEI authors’ August 2025 statement says only low-certainty evidence exists on the benefits of the treatments they reviewed. That is an evidence finding, not a law.

Read the summary PMC — puberty blockers systematic review McMaster HEI — systematic reviews related to sex-rejecting procedures PMC — hormone therapy systematic review PMC — mastectomy systematic review

Ludvigsson et al. 2023: Hormone treatment for children with gender dysphoria (Acta Paediatrica)

Jonas F. Ludvigsson and colleagues published a systematic review (a careful look at all the studies, following a published search method) of hormone treatment in children with gender dysphoria — mood and daily life, thinking, body composition, and metabolic markers. This is a peer-reviewed evidence paper.

Of 9,934 records, 24 studies were relevant: 21 of puberty blockers (GnRH analogues) in adolescents and 3 of hormones of the opposite sex without puberty blockers first. No gold-standard random-assignment trials were found.
The few longer follow-up studies were hampered by small numbers and many dropouts. Long-term effects of hormone therapy on mental health could not be judged.
Puberty blockers delay bone growth and bone-strength gain. That density was found to partially recover during later opposite-sex hormones when studied at age 22.
Evidence to assess those effects is not enough. The authors offer a research checklist for future studies. DOI 10.1111/apa.16791.

Read the summary Wiley — Acta Paediatrica (DOI 10.1111/apa.16791)PubMed — Ludvigsson et al. 2023

Sweden — Socialstyrelsen / SBU: Care of children and adolescents with gender dysphoria (December 2022)

Sweden’s health board (Socialstyrelsen) updated national guidelines after its evidence agency (SBU) looked at all the studies and found the evidence not enough to judge puberty blockers and hormones of the opposite sex in adolescents. This card is that official evidence and guideline record.

SBU’s review concluded that existing scientific evidence is not enough to judge the effects of puberty blockers and opposite-sex hormones on gender dysphoria, mental health, and quality of life in adolescents.
At group level, Sweden’s health board assesses that the risks of puberty blockers and other sex-rejecting procedures are likely to outweigh the expected benefits.
It gives a weak “don’t, except rarely” recommendation: puberty blockers (GnRH analogues), hormones of the opposite sex, and double mastectomy may be given in exceptional cases, preferably in research.
This is a national restriction and research-setting recommendation.

Read the summary Socialstyrelsen English summary (PDF)SBU — Hormone treatment of children and adolescents with gender dysphoria

Finland — COHERE: Medical treatment methods for dysphoria associated with variations in gender identity in minors (June 2020)

Finland’s public-care council (COHERE / PALKO) issued a recommendation on which medical treatments for gender dysphoria in minors belong in public healthcare. Research data on those treatments in minors, it states, is limited.

Psychosocial support should be provided in school, student, and primary healthcare. Psychiatric treatment for concurrent illness is arranged locally; no conclusions can be drawn on the stability of gender identity during an active psychiatric disorder.
Diagnostics, assessment of medical need, and planning are centralized at HUS and TAYS. Puberty suppression may be initiated only case-by-case after careful diagnostic examinations if indications are present and there are no contraindications.
Hormonal interventions that alter sex characteristics before 18 may be considered only if identity as the other sex is permanent and causes severe dysphoria, the young person can understand irreversible lifelong hormone therapy, and no contraindications are present.
Surgical treatments are not part of the treatment methods for dysphoria caused by gender-related conflicts in minors.

Read the summary COHERE Finland — minors recommendation (PDF)COHERE recommendations index