The Nazis aimed to control and indoctrinate German youth through education and youth groups to support the regime for generations. Boys and girls were divided into separate groups from ages 6 to 18 focused on traditional gender roles to produce strong men and mothers. At school, children received a Nazi-focused education from teachers who underwent Nazi training, with lessons shaped to promote Nazi ideology especially in subjects like history and biology. However, historians note the indoctrination's effects were limited and many youth began rebelling against forced membership near World War 2's start, and 12 years of Nazi rule did not completely erase previous cultural influences.