Autism spectrum disorder (ASD) is caused by a combination of genetic and environmental factors. Genetic predisposition plays a major role, supported by evidence like strong correlations in identical twins and increased risk in siblings. Environmental factors, especially those related to prenatal and perinatal periods such as certain drugs during pregnancy, premature birth, lack of oxygen at birth, advanced parental age, and prenatal exposure to pollutants, can increase the likelihood of developing autism in genetically predisposed individuals. There is no evidence supporting vaccines as a cause of autism. The causes are multifactorial and vary among individuals, with ongoing research to better understand these complex interactions.
