Why does there have to be a separate system for juvenile and adults?

The juvenile court movement started in the United States in the early 1900’s. This was a time when similar movements governing child labor, child abuse and neglect, etc., were popular. The movement for juvenile courts was established by persons who believed that children to be treated differently than adults because they did not possess the same level of knowledge and maturity as adults; thus, they should not be held to the same legal standards as adults.