PROJECT SUMMARY Transgender and gender diverse (TGD) youth have a gender identity different from society's expectations based off their sex assigned at birth. Stigma, distress with pubertal changes associated with sex assigned at birth, and societal expectations of gender and beauty, are factors that can affect a TGD youth's relationship with their body, eating, and exercise. TGD youth are at higher risk of disordered eating behaviors (DEB) and experience unique cognitions that contribute to DEB; however, they have historically been excluded from DEB research. Additionally, extant DEB research with TGD youth is limited due to a lack of representation of subpopulations of TGD youth participants, mainly non-binary youth and TGD youth of color. These gaps in research limit the field's ability to provide culturally specific clinical care to a vulnerable group with unique health disparities associated with DEB. To advance this care, we urgently need to extend DEB research beyond cisgender females and recruit racially/ethnically diverse samples of TGD youth across the spectrum of age, gender identity, and access to gender-affirming support/resources. A novel approach to address these knowledge gaps is to implement community-engaged research methods to develop and evaluate a tailored measure of DEB in TGD youth. The proposed research has three aims: 1. Obtain qualitative data from a diverse sample of TGD youth on facilitators of and barriers to research participation to improve recruitment protocols for the remaining aims, 2. Use focus groups and cognitive interviews to develop and refine a measure of DEB in TGD youth, 3. Evaluate the psychometric properties of the DEB measure and assess correlations between DEB and TGD-specific risk and protective factors. A TGD youth advisory board and community consultant with expertise in DEB in TGD youth will actively participate in research protocols throughout the 4-year grant proposal. Research activities include designing recruitment matrices, conducting qualitative interviews and analyses, and disseminating results. The data from this innovative study will inform a longitudinal study on changes in DEB throughout: 1) eating disorder treatment in TGD youth with DEB, 2) pubertal development in TGD youth, and 3) gender-affirming care in TGD youth receiving gender-affirming medications such as testosterone, estrogen, and/or puberty blockers. This proposal is highly consistent with NIMH's priority of expanding research involving sexual and gender minority (SGM) populations to reduce the mental health disparities experienced by vulnerable SGM communities. Dr. An Pham is an Adolescent Medicine physician with clinical expertise in gender-affirming medical care and this K23 Career Development Award will fill gaps in her training and provide her with the necessary mentorship and skills to become an independent investigator on youth-engaged DEB research in TGD youth. Specifically, Dr. Pham will work closely with her mento...