Marni Sommer, DrPH, MSN, RN, has worked in global health and development on issues ranging from improving access to essential medicines to humanitarian relief in conflict settings. Dr. Sommer's particular 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 sexual health, and the implementation and evaluation of adolescent-focused interventions. Her doctoral research explored girls' experiences of menstruation, puberty and schooling in Tanzania, and the ways in which the onset of puberty might be disrupting girls' academic performance and healthy transition to adulthood. Dr. Sommer presently leads the Gender, Adolescent Transitions and Environment (GATE) Program, based in the Department of Sociomedical Sciences. GATE explores the intersections of gender, health, education and the environment for girls and boys transitioning into adulthood in low-income countries and in the United States. GATE also generates research and practical resources focused on improving the integration of menstrual hygiene management and gender supportive sanitation solutions into global humanitarian response.