Nonconforming gender expression and associated problematic smartphone and internet use among Chinese adolescents.

GNC is positively associated with the severity of PSU and PIU among Chinese adolescents, with male gender-nonconforming adolescents being more vulnerable to PSU. These results highlight the importance of implementing education on gender expression diversity in schools to create an inclusive school environment, which may potentially help prevent PSU and PIU among gender-nonconforming adolescents.