In many studies on gender-diverse youth (GDY), those whose gender identity and sex assigned at birth do not fully align, researchers cite the 2017 Youth Risk Behavior Survey finding that 1.8% of US high school students identify as “transgender.”1 This was the first nationally representative prevalence estimate of GDY and was higher than previous estimates. However, the question assessing gender identity (“Do you identify as transgender?”) likely underrepresents the prevalence of GDY because many do not identify with the word “transgender.” As an alternative, researchers recommend a 2-step question: (1) What was your sex assigned at birth? (2) Which of the following best describes your gender identity?2,3Much of the research involving GDY has been conducted in clinical settings, in which there is a predominance of white and masculine-identified youth.4–7 GDY of color, specifically Black and Hispanic transgender women, are more likely than other gender-diverse people to experience violence and socioeconomic disadvantage because of systemic racism and transmisogyny.8 These systemic inequities likely result in decreased access to gender-affirming care. Because access to gender-affirming care is associated with improved health outcomes,9 identifying groups who are not receiving care is vital to creating more equitable access to care for all GDY, but especially Black and Hispanic transgender women. The goal of this study was to assess the prevalence of GDY in a school-based sample to (1) document the prevalence of GDY by using a 2-step approach and (2) examine prevalence by race and ethnicity and gender identity.In October of 2018, a modified version of the Youth Risk Behavior Survey was distributed to ninth- to 12th-graders in 13 high schools, reaching 91% of the ∼4930 students in a Northeastern midsized city school district. The survey included a 2-step gender identity question: (1) “What is your sex (the sex you were assigned at birth, on your birth certificate)?” with the options “female” and “male” and (2) “Which of the following best describes you (select all that apply)?” with the options “girl,” “boy,” “trans girl,” “trans boy,” “genderqueer,” “nonbinary,” and “another identity.” Of 4730 returned surveys, 37 were found to be unreadable, and 243 were deemed mischievous responders or had <20 answered questions. An additional 1282 participants skipped questions regarding race and ethnicity or gender identity and were excluded from this analysis. Descriptive statistics were calculated by using Stata/SE, version 15.1 (Stata Corp, College Station, TX).Of 3168 surveys analyzed, incongruence between gender identity and sex assigned at birth was identified in 291 participants (9.2%; Table 1). This prevalence was 7.1% among white youth and higher among American Indian, Alaskan Native, Asian American, Pacific Islander, and/or Native Hawaiian, Hispanic, Black, and multiracial youth (13.4%, 14.4%, 9.9%, and 8.7% respectively). Gender identity among GDY was split between masculine (29.9%), feminine (38.8%), and nonbinary identities (31.3%), with 38 (13.1%) selecting >1 identity (Table 2).Nearly 10% of high school students surveyed reported a gender-diverse identity. The prevalence of GDY in this study is 5 times higher than current national estimates from a study involving 10 states and 9 urban school districts.1 Although these data were collected from a single urban school district, the findings may approximate a less biased estimate of the prevalence of youth with gender-diverse identities, given how gender identity was operationalized.Additionally, the demographics of GDY in this school-based study differ from those of GDY accessing gender-affirming care in the same region. A 2018 survey from the only pediatric gender clinic in the region found the majority of patients identified as white (88%) and masculine (65%).10 This clinic’s findings are consistent with other pediatric gender clinics across the United States4–7 and highlight the lack of diversity among youth receiving gender-affirming care, especially with respect to race and/or ethnicity and gender. These disparities suggest that gender clinics may not be reaching youth at the highest risk of experiencing violence, victimization, socioeconomic disadvantage, and health disparities: Black and Hispanic transgender women. Researchers should consider using a 2-step approach, as outlined above, to better reflect prevalence of GDY, particularly in statewide and national level surveys, with sample sizes allowing analysis of potential differences in gender identity by race and/or ethnicity and age. In addition to encouraging continued refinement of gender identity measures, particularly for youth, these findings underscore the need to re-evaluate systems and structures that continue to perpetuate inequities in access to gender-affirming care.We thank the Allegheny County Health Department for their role in data collection and for the use of these data. We are grateful to Pittsburgh Public School Board leadership for their collaboration.