Photo: Georgios Tzanakis / Wikimedia Commons, CC BY 3.0
The summary of a newly funded federal study of double mastectomies for gender states its expected result in advance: "They expect that top surgery will reduce the body's stress burden." It adds that the evidence "could strengthen support for access to gender-affirming care," and describes as established that "we know that top surgery improves mental health." No results have been published.
In September 2026, the Canadian Institutes of Health Research (CIHR), Canada's federal health research funding agency, approved two four-year grants for gender surgery research in Toronto, totalling $1,399,207.
The grants came through CIHR's "Advancing 2S/LGBTQI+ Health Through Research" program, which funded 22 teams.
The two grants
1. $700,000 to the University of Toronto (CIHR record). "Gender-Affirming Chest Surgery and Allostatic Load in Transgender Men and Non-Binary Individuals." Six principal investigators, led by Massieh Moayedi and including Dr. Kathleen Armstrong. The study looks at double mastectomies for gender and "allostatic load," a measure of the long-term physical effects of stress, using blood tests and surveys before and after surgery.
2. $699,207 to Women's College Hospital (CIHR record). "Improving Gender-Affirming Surgical Care Through Digital Patient-Reported Outcomes: Implementing the GENDER-Q at Women's College Hospital." Principal investigator: Dr. Armstrong. Patients seeking gender surgery will complete a questionnaire, the GENDER-Q, before appointments, with results added to the electronic health record.
What the lead surgeon said
In an Oct. 21 article in Canadian Healthcare Technology, Dr. Armstrong called the funding "an important commitment by the Canadian government to the health and rights of transgender people and the broader 2SLGBTQI+ community, at a time when we have seen other countries move away from these commitments."
Age range
The CIHR grant records do not state an age range, and there is no indication either way that minors are included. For context: Women's College Hospital has no minimum age for surgery, and told the National Post in 2023 that most of its patients are over 18. Dr. Armstrong was first author of a May 2026 BMJ Open study of 35 females aged 13 to 18 who were seeking or had undergone double mastectomies.
International context
Several countries have reviewed the evidence for gender medicine in minors and changed course:
- England: The Cass Review (2024) described the evidence base as "remarkably weak." NHS England ended routine prescribing of puberty blockers for gender dysphoria.
- Sweden: The National Board of Health and Welfare (2022) limited puberty blockers and cross-sex hormones for minors to exceptional cases.
- Finland: COHERE Finland (2020) recommended psychosocial support first for minors and advised against surgery for minors.
- United States: The Department of Health and Human Services review (2025) rated the evidence for medical transition of minors as "very low" certainty.
Canada has not carried out a comparable national evidence review.