In Western society in the 21st century, educators make many assumptions about children’s development. Progress is measured against published norms. Some people prefer to call these milestones, and children’s arrival at these significant points is eagerly discussed and compared. It may, therefore, be surprising to discover that the widely-held views of today about the ages and stages by which children should achieve particular milestones are relatively new and not universally held to be true. The extent to which nature or nurture determines development is a common debate, but one thing is certain - the educators’ role is to ensure the best possible environment for growth, learning and development.