Alix S. Winter, Christine Fountain, Keely Cheslack-Postava, and Peter S. Bearman:

Rates of autism diagnosis in the United States have historically been higher among more advantaged social groups—Whites and those of higher socioeconomic status (SES). Using data from all births in the state of California in 1992 through 2016, we find that these trends reversed during our study period. By 2018, diagnosed autism incidence rates for 3- to 6-y-old children were higher for children of Black and Asian mothers than children of non-Hispanic White mothers and were higher for children of lower SES than of higher SES parents. These reversals point to the fundamental role that access to knowledge and resources plays in driving increased autism prevalence and shifting patterns of autism cases over the past quarter-century.