Research is beginning to point to the factors that cause Autism. These include a complicated tapestry of environmental and genetic factors that interact in ways we don't yet understand.
Genetic factors may include either genetic mutations or on of hundreds of genes related to increased risk. About 15% of cases of Autism Can be attributed directly to genetic factors.
Genetic factors interact with environmental factors including age of both parents and prenatal health of the parent and the child.
There are many factors that are still not well understood. Researchers are currently looking at the role of the immune system.