Belief structures being what they are, I will not present my antidotal evidence to the contrary. I would like to see some causational proof, other than produced videos and such.
My son's autism did not become evident until he was about 3 but initially was diagnosed as retarded. He hit all the milestones on time and could repeat his name at a year but at 3 he just would NOT listen. Today at 14 he has come further then I ever though possible.