Background: Increasing numbers of children/adolescents experiencing gender dysphoria/incongruence are being referred to specialist gender services. Services and practice guidelines are responding to these changes.

Aim: This systematic review examines the numbers and characteristics of children/adolescents (under 18) referred to specialist gender or endocrinology services.

Methods: Database searches were performed (April 2022), with results assessed independently by two reviewers. Peer-reviewed articles providing at least birth-registered sex or age at referral were included. Demographic, gender-related, mental health, neurodevelopmental conditions and adverse childhood experience data were extracted. A narrative approach to synthesis was used and where appropriate proportions were combined in a meta-analysis.

Results: 143 studies from 131 articles across 17 countries were included. There was a twofold to threefold increase in the number of referrals and a steady increase in birth-registered females being referred. There is inconsistent collection and reporting of key data across many of the studies. Approximately 60% of children/adolescents referred to services had made steps to present themselves in their preferred gender. Just under 50% of studies reported data on depression and/or anxiety and under 20% reported data on other mental health issues and neurodevelopmental conditions. Changes in the characteristics of referrals over time were generally not reported.

Conclusions: Services need to capture, assess and respond to the potentially co-occurring complexities of children/adolescents being referred to specialist gender and endocrine services. Agreement on the core characteristics for collection at referral/assessment would help to ensure services are capturing data as well as developing pathways to meet the needs of these children. PROSPERO registration number CRD42021289659.