Even as research in the United States pointed to biological and neurological conceptions of autism, the French continued to support a psychogenic origin for the disorder, impacting state policy and medical norms for decades. This position energized conflict between professionals and parents concerning expertise, leading to political and legal changes at the end of the twentieth century. By the twenty-first century, French autists entered the debate to transform its parameters and assert their own position as experts on autism, reconceiving the disorder outside of childhood to a limited degree. Perpetual Children reveals the international dimension of the story of autism and how the French context provides a different perspective on its history.