Precisely. Plus, if autism has a genetic component, one would suspect that the Amish draw from a different gene pool than the general population.
While interesting, this anecdotal (I don't think we've ever seen) report has very little persuasive power or scientific merit.
I have known some Amish. Perhaps it wasn't autism, but I've seen several "special needs" Amish children.
I know a family that had a bright and ordinary three year old. They took him for a routine vacination ... three days later he was Autistic. Those parents went to great lengths to research this, only to find out that many parents had the exact same experience. Research does indicate that the mercury compounds used as preservatives tend to pool in the bottom of the serum. If the bottle is not shaken before a dose is given, the mercury concentration will increase. The last kid vaccinated with the bottle gets nailed for life.
This is another major coverup in progress, since this problem was identified ten years ago.