No, the exact cause of Autism, and its many related disorders, is not known. Some people however do speculate that it may be an inherited gene.

People also speculate many things,mercury, vaccines, and complications resulting from diseases caused by virus and bacteria. I personally suggest that the apparent rise in autism is that parents are somehow damaging the DNA they "donate" to the child resulting in a broad range of autistic disorders... that could explain why families with no history have autistic children

None of the above. Think about it we have never had a virus or bacteria that was only contagious in children. We also have never linked a specific bateria or virus infection to the onset of the desease. Also if it was caused by a virus or bacteria adults would get autism as well. And that vaccine theory is a total crock. Children get fewer immuniziations with lower doses of mecury in them then when I was a baby 30 years ago. And you never heard of autism till that one TV show in the 80's. Now just about everyone knows one person who has a family member who has it. If it really was the vaccines it would be the other way around. And don't give me the whole spew about "we've learned to detect it better." The sharpest rise in the rates of Autism happened when they changed the diagnoses criteria from extreamly strict to very libral after the government said they were going to cut the funding for research due to the low numbers of people who had it. In all honesty I think this has a completely parental cause. Too many women too old to be having babies loading up on fertility drugs and the other group would be the reacreational drug users (including pot) who damage their reproductive cells "having a good time". But as is usally the case it's so much easier to blame an outside source then ourselves. Especially when some thing bad happens to our children.