Sean D. Young, PhD, MS, is an Assistant Professor in the Department of Family Medicine and Center for Behavior and Addiction Medicine at UCLA. Dr. Young studies HIV prevention decision-making and testing behavior in the U.S., Peru, and South Africa. He also has conducted extensive user experience research and development, designing and evaluating social media and health behavior change methods and social media “apps” for HIV prevention, addiction medicine, and general health. He has spent the past 7 years studying the relationship between social media and HIV prevention/sexual risk behaviors among Los Angeles homeless youth, African American and Latino MSM, Peruvian MSM, and American and Iranian college undergraduates. He is the Primary Investigator of the HOPE UCLA study, the first intervention trial to assess whether social networking technologies can be used to deliver peer-led HIV prevention information to increase HIV testing among African American and Latino MSM. He is currently replicating this study among Peruvian MSM, in Lima, Peru. Dr. Young’s clinical work is focused on designing and evaluating engaging electronic platforms and medical decision-making tools.