PROJECT SUMMARY/ABSTRACT The Institute of Medicine’s report on “The health of Lesbian, Gay, Bisexual, and transgender People,” called for NIH-supported research to address the methodological challenges that have impeded research on the health of transgender people – specifically, to improve strategies for reaching, larger, more diverse samples of transgender persons in the United States. Historically, research on sexual and reproductive health (SRH) has excluded or misclassified transgender, nonbinary, and intersex (TNBI) people due to presumptions that pregnancy and related outcomes can be experienced solely by cisgender women. However, TNBI people plan for and carry pregnancies, and thus require high-quality and evidence-based healthcare. Despite this need, existing data on the SRH needs of TNBI populations primarily come from convenience samples-- small in size and/or limited in geographic scope. The dearth of representative data has meant, critically, that SRH providers do not have adequate evidence upon which to rely to ensure that the SRH needs of their TNBI patients are met within existing healthcare services--thereby contributing to lower quality care and SRH disparities among these populations. And while data on transgender and nonbinary people are scarce, data on intersex people are even scarcer. Consequently, this study aims to test methods of improving the research participation, retention, and quality of collected data among TNBI people in the United States. The specific aims include: (1) recruit a large, diverse sample of TNBI people from across the United States, (2) collect longitudinal data on core SRH outcomes, and (3) improve retention and data quality among TNBI participants in SRH research as compared to standard methods. To achieve these aims, we will implement a four-arm, parallel design, randomized control trial that randomizes participants to receipt of zero, one, or two novel survey features in their online survey: a gender-inclusive anatomical organ inventory for screening into survey logic, and/or customizable survey language to personalize their survey experience. The control group will be randomized to screening based on a 2-part gender identity question, and use of standard medical terms. The research will address challenges encountered in previous SRH research with TNBI populations and will contribute to the evidence around best practices for data collection with other populations historically characterized as “hard-to-reach” in the context of SRH, public health research, and clinical care. The evidence generated by this study could have wide-ranging impacts—including refined determination of research and clinical care eligibility, improved research participation, and better healthcare screening and treatment for TNBI populations. Beyond SRH and advancing the evidence-based for TNBI people, this novel survey methodologies tested in this study could be applied broadly to advance public health research approaches and...