John Santelli, MD, MPH  is a Professor and Chair of the Heilbrunn Department of Population and Family Health at the School of Public Health at Columbia University and a Senior Fellow at the Guttmacher Institute.  John is a pediatrician and adolescent medicine specialist. Prior to moving to New York 3 years ago, he held a variety of positions at the U.S. Centers for Disease Control and Prevention (CDC). He has conducted research on HIV/STD risk behaviors, programs to prevent STD/HIV/unintended pregnancy among adolescents and women, school-based health centers, and research ethics.