Stephen Matthews is Professor at the University of Toronto and Director of Research at the Alliance for Human Development at Mt Sinai Hospital, Toronto. He is recognised internationally for his research into the factors, particularly cortisol-like hormones, which influence development of the brain of the fetus during pregnancy and in early childhood. He is co-founder of the Canadian Society for the study of the Developmental Origins of Health and Disease (DOHaD) and co-Director of the Ontario Birth Study. His work with UNICEF and other international organizations, will help determine the impact of preconception interventions on infant and childhood brain development.