During the 20th century, mass education replaced trade skills as the primary way to prepare children for adulthood. This raised questions about whose values should be taught in public schools, how to ensure student success, and whether education funding should only go to public schools or could follow students to other options. Over the century, compulsory attendance laws were established, the professionalization of teaching occurred, and Supreme Court cases established parents' rights to direct their child's education. Debates continued over the teaching of subjects like evolution, prayer in schools, and school choice.