Parenting in the early years has a critical influence on children's development, whether one examines positive outcomes, such as prosocial behaviour, empathy or school performance, or negative outcomes, such as aggressive behaviour, bullying or school dropout. In Canada, Dr J Douglas Willms' analysis (1) of the National Longitudinal Survey of Children and Youth found nearly 30% of children have cognitive or behavioural problems serious enough to make them vulnerable in the sense that unless there is a concerted effort to intervene on their behalf, they would be prone to experiencing problems throughout their childhood and young adulthood. After examining the most important determinants of these problems, Willms concluded that "sensitive, responsive parenting is the single most important benefit children can receive during their early years". In the United States, a megastudy (2) by the National Institute of Child Health and Human Development, which measured the impact of both child care and parents on children's development, concurs that parenting is the primary influence on children's development.