What are the 5 main Causes of Autism ? 📚 While the exact causes of ASD are not fully understood, research suggests that genetic and environmental factors, as well as brain development and parental age, may play a role. Studies have shown that up to 90% of the risk for developing ASD is due to genetic factors, and certain genetic mutations and chromosomal abnormalities have been linked to an increased risk of the disorder. Environmental factors such as prenatal exposure to toxins and maternal in