Wyoming becomes the 49th state to require coverage of autism.

On April 19, 2019, Wyoming became the 49th state to address autism insurance coverage in state-regulated plans. Wyoming Insurance Commissioner Tom Glause announced that all plans with mental health coverage — including large group, small group, and individual plans — will be barred from excluding evidence-based treatment for autism spectrum disorder (ASD). Source: https://www.autismspeaks.org/

Here is the list of 49 states that require coverage of autism.
Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Texas, Utah, Vermont, Virginia, West Virginia, and Wisconsin. Washington state is providing insurance coverage via a lawsuit and follow-up regulations. Georgia, Hawaii, Mississippi, North Carolina, North and South Dakota, Idaho, Wyoming 

Source: https://www.ncsl.org/research/health/autism-and-insurance-coverage-state-laws.aspx