Gong T, et al. - In this large observational study with 1,579,263 children, the relationships of maternal/paternal asthma as well as of prenatal exposures to β2-agonists and other asthma medications with offspring autism spectrum disorder (ASD) were examined in cases and controls selected from the population as well as biological relatives with different degrees of relatedness. Overall, 22,894 ASD cases were compared to 228,940 age-, county- and sex-matched controls. A slightly higher risk of ASD was noted in offspring in relation to parental asthma. Familial factors did not appear to have a confounding impact on the observed increased risk by maternal asthma. Asthma medications during pregnancy were not related to ASD in offspring.