Mika Gissler is a full Research Professor and hold faculty appointments at the National Institute for Health and Welfare, the University of Turku, Finland, the University of Oulu, Finland, and Karolinska Institute, Stockholm, Sweden. His main research focus has been in utilization of routinely collected health and welfare registers with experience in using registers in all Nordic countries (Finland, Sweden, Norway, Denmark and Iceland), and in several European countries (e.g. Germany and Estonia). Professor Mika Gissler’s research interests include perinatal and infant health, childhood and adolescent health, sexual and reproductive health, mental health, migrant health and use of health care services. Increasingly, the studies have included a longitudinal component, usually from the prenatal period until adulthood.