What's the primary cause for autism or autistic spectrum disorder?

Cause Unknown: Risk factors include genetics, pre-/perinatal factors, neuroanatomical abnormalities, & environmental factors. No single gene can account for autism. There seems to be multiple genes involved. Possibly maternal gestational diabetes, maternal/paternal age over 30, bleeding after first trimester, use of prescription medication during pregnancy, & meconium in the amniotic fluid but not conclusive.

No known cause yet: ASD has a strong genetic component. Therefore patient must be evaluated by a team of expert. It is important to have a definitive diagnosis of ASD to begin treatment regiment as early as possible.