Questioning Gender Identity in Adolescent Population Research: Development and Pilot Testing of the Gender Identity Questions for Adolescents

Standardized questions to assess gender identity within adolescent population research are currently lacking. This study aims to develop and pilot brief and user-friendly self-report questions, the Gender Identity Questions for Adolescents (GIQA). A four-phase mixed-method study consisting of a literature search, expert panel, cognitive interviews, and pilot study was employed. First, using insights from nine existing questionnaires on gender identity, the GIQAVersion 1 was drafted, including different modes of questioning and responding (categorical and ordinal). Second, an expert panel (n = 5) evaluated the GIQAVersion 1 and recommended using concise and clear item formulation resulting in the use of the two-step method (i.e., sequentially asking about sex at birth and gender identity), resulting in the GIQAVersion 2. Third, cognitive interviews with cisgender (n = 10), transgender (n = 1), and nonbinary adolescents (n = 1) indicated no clear inclination for categorical or ordinal response options, both were kept in the GIQA Version 3. Fourth, quantitative and qualitative analysis of pilot data among adolescents (n = 329) showed that the response mode influenced outcomes, with categorical options yielding greater identification of cisgender (92.8%) and transgender (1.6%) adolescents, compared to ordinal questions, respectively 89.8% and 1.0%. A higher incidence of missing values was noted with ordinal questions, although both versions demonstrated efficacy in adolescents. It is recommended to consider the research goal when selecting between the categorical and ordinal versions. Adding the GIQA in population (health) research will make this type of research more inclusive and provide insight into the health and health behaviors of gender-diverse adolescents.