elmhar gave great points scientifically, something I can't do

All I can give is my personal side.
I am almost the opposite of 9CatMom. I have AS/HFA (currently dxed as AS but I have a speech and cognitive delays), and I have what is suspected to be Temporal Lobe Epilepsy. I had no head or birth trauma, and I never was deprived of oxygen. The labor was average as well as the delivery. I came out fine, however, my mother had to stay in the hopital a few weeks after my birth because of a doctors fault.
Personally, from what I know I lean more towards Autism being genetic factor along with possible environment causes, and Epilepsy having a genetic factor with brain abnormalties.
SGH