One of the paper’s authors, Professor Mikael Landén of the Karolinska Institute, said: “against the background of almost non-existent long term data, we conclude that GnRHa treatment in children with gender dysphoria should be considered experimental treatment rather than standard procedure.”

The findings, published in the medical journal Acta Paediatrica, come at a time when cases of gender dysphoria and applications for hormonal treatment are soaring. Though the UK’s only dedicated gender identity clinic for under-18s, the Tavistock Centre, was closed down last year, its Gender Identity Development Service (GIDS) still had over 5000 referrals in its final full year of operation. Just a decade earlier, the annual figure had been less than 250. 

Hormone therapy is also widely available for children across Europe. In twenty EU member states, the practice is provided to minors under the same conditions applied to access any other medical treatment. Sweden discontinued the policy in February of last year, except for in rare cases, on the recommendation of the Karolinska Hospital. The country had previously seen its own spike in gender dysphoria, with an 1500% increase in referrals among teenage girls since 2008, according to the National Board of Health and Welfare. A 2021 report showed that 13 children in Sweden suffered serious side effects and medical injuries from taking puberty blockers, including osteoporosis.

The Karolinska academics and SBU observe “substantial limitations in earlier research on gender dysphoria”. The researchers also question whether data can be “generalised to individuals with gender dysphoria outside your study centre and the study country”.