Since 2001, 44 states have begun requiring some insurance plans to cover ABA for children diagnosed with autism spectrum disorder. But the rules are all different, making for uneven coverage across states. The mandates don't apply to those companies, often large, that insure their own workers. In some states, small businesses are not required to offer coverage. Depending on the state, coverage may be available to state employees, Medicaid recipients and people purchasing insurance in the marketplaces created under the Affordable Care Act. Amy Weinstock, founding director of the Autism Insurance Resource Center at UMass Medical School, explains the Massachusetts autism law.