Mapping diversity in gender identity and gender roles across sex and age in the Dutch general population: a large-scale cohort study.

Abstract

Background: Knowledge of diversity in gender identity and gender roles in the general population is limited. This study aimed to report the prevalence estimates of gender identity and gender roles among the adult general population, stratified by age and sex.

Methods: In the third general assessment of the prospective Dutch Lifelines Cohort Study, conducted between 2019 and 2023, sex and current gender identity were assessed using a self-reported categorical item, in which participants aged 18 years and older could indicate their sex assigned at birth (male or female) and current gender identity (man or woman), or select the option with a free-text field. Two separate dimensional measures assessed adherence to feminine and masculine gender roles. Using a cross-sectional study design, we describe the distribution of gender identities and adherence to gender roles, stratified by age and sex as registered by the municipality. Differences herein are assessed via independent t-tests and ANOVA.

Findings: A total of 63,190 participants (mean age = 55.4 years [SD = 12.6]) were included in the study. Most participants identified as cisgender (36,835 [58.6%; 95% CI = 58.2-58.9] cisgender women; 25,893 [41.2%; 95% CI = 40.8-41.6] cisgender men). 66 (0.11%; 95% CI = 0.08%-0.13%) participants identified as non-cisgender. Among cisgender participants registered as males, masculine gender role scores increased across age groups, with younger individuals (18-30 years) scoring lower (M = 9.3, SD = 1.2) than older individuals (71-97 years; M = 9.7, SD = 1.0; F _(5,25925) = 35.5; p < 0.0001; η² = 0.008 [95% CI = 0.006-0.010]). A similar pattern was observed for adherence to feminine gender roles among cisgender participants registered as females, where younger individuals (M = 9.1, SD = 1.2) scored lower than older individuals (M = 9.7, SD = 1.0; F _(5,36900) = 137.2; p < 0.0001, η² = 0.018 [95% CI = 0.016-0.021]). Cisgender participants registered as male reported stronger adherence to masculine roles (M = 9.6, SD = 1.0), than their female counterparts to feminine roles (M = 9.3, SD = 1.2; t_(60,459)=27.7; p < 0.0001, Cohen's d = 0.218 [95% CI = 0.202-0.234]).

Interpretation: Although effect sizes are small, younger and female individuals indicate greater diversity in gender roles than older and male individuals, respectively. This shows that diversity in gender role adherence is common. A limitation of this study is the relatively older sample, which limits representation of younger individuals and may affect generalizability. These findings have implications for clinical practice and policy, as recognizing gender role diversity could help healthcare providers tailor interventions and assessments. Given the small but meaningful effect sizes, continued research on gender roles and their health impact across age groups is warranted to inform gender-sensitive policies.

Funding: The Dutch Ministry of Health, Welfare and Sport, the Dutch Ministry of Economic Affairs, the University Medical Center Groningen (UMCG), Groningen University, the Provinces in the North of the Netherlands (Drenthe, Friesland, Groningen) and ZonMw (The Netherlands Organization for Health Research and Development).