There is no connection to cannabis and Autism, however there are now thousands of man made chemicals throughout the environment (roundup for instance) that are far more likely to cause birth defects.  Cannabis if you care to actually look at the facts is the safest substance known to mankind.  There has never been an overdose death from cannabis in the entire history of humankind.  Cannabis is FAR safer than Alcohol, Prescription Drugs, Tobacco, and probably half the food in the grocery store.   Seriously learn the facts.