Marni Sommer, Professor of Sociomedical Sciences at the Columbia University Mailman School of Public Health, has worked for over twenty years in global health and development on issues ranging form improving access to essential medicine to humanitarian relief in post-conflict settings. Dr. Sommer's areas of expertise include conducting participatory research with adolescents, understanding and promoting healthy transitions to adulthood, the intersection of public health and education, gender, and adolescent focused interventions. She has conducted numerous projects on menstrual health and hygiene, ranging from research in low-resource countries, to humanitarian settings, to engaging with with menstrual health practice and policy more broadly, both in the United States and globally. Dr. Sommer presently leads the Gender, Adolescent Transitions, and Environment (GATE) Program, which explores the intersections of gender, health, education, and the environment for young people and women around the world. GATE also generates research and practical resources focused on improving the integration of menstrual health and hygiene and gender-supportive sanitation solutions into urban settings and global humanitarian response. She is the President of Grow and Know, a non-profit that develops and disseminates puberty books for girls and boys around the world, and an Executive Editor for the journal Global Public Health.