There are a variety of theories about the cause of autism, but the exact cause is still unknown. Some researchers believe that a combination of genetic and environmental factors may be involved in the development of autism. There is evidence to suggest that certain genes may increase the risk of developing autism, but no specific gene has been identified as the sole cause. Additionally, environmental factors such as prenatal exposure to certain chemicals or infections may also play a role. It is important to note that vaccines do not cause autism, as multiple scientific studies have debunked this myth. Overall, more research is needed to fully understand the causes of autism.