Stephen Cohen did his undergraduate work at the University of Toronto (Canada) before moving to Princeton University (USA), where he went on to earn his Ph. D. in 1983. He next spent three years at MIT as a postdoctoral fellow in Harvey Lodish's lab, then moved to Germany, where he worked in Herbert Jäckle's labs in the Max-Planck-Institut für Entwicklungsbiologie (Tübingen) and the Institut für Genetik und Mikrobiologie (Munich) until 1989. He returned to the United States to take an assistant professorship in the Department of Cell Biology, Baylor College of Medicine that same year, and was named a Howard Hughes Medical Institute assistant investigator in 1990. He moved back to Germany in 1993 as Group Leader at the European Molecular Biology Laboratory in Heidelberg, where he was subsequently appointed Senior Scientist and, in 1996, Head of the Developmental Biology Unit. He serves on the editorial boards of Mechanisms of Development and Developmental Cell, and from 2006 will join the editorial board of Genes and Development, and serve an editor at Developmental Biology. His research group uses molecular and genetic approaches to understanding how morphogen gradients are established and how they control tissue growth during development and on the roles of microRNAs in development and metabolism.