Final answer:
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with both genetic and environmental risk factors. Genetics plays a primary role in the development of ASD, with variants of several genes correlating with the disorder. Environmental factors, such as exposure to pollutants, may also act as triggers for ASD.
Step-by-step explanation:
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with risk factors that can contribute to having a second child with ASD. While the exact causes of ASD are largely unknown, researchers believe that genetics plays a primary role. Variants of several genes have been found to correlate with the presence of ASD, and for any given patient, many different mutations in different genes may be required for the disorder to develop. Environmental factors, such as exposure to various pollutants, have also been suggested as potential triggers for ASD, but more research is needed for definitive answers.