"Further, the American Autism Society (or somesuch) says that the precise cause of autism is not known, but that it is probably genetic."
I don't think the thimerosol argument is linked to autism from biological sources. It's alleged mercury poisoning exhibits the same symptoms as forms of what we've called autism.
Their could be other environmental causes.
The relative surge in autism could be environmental, could be due to increased reporting and disgnosis, or could be due to trends of older women having children. I think the last has been discounted. The surge has an interesting correlation with thimerosol's increased use. The symptoms presented also correlate with mercury poisoning (of very young children). Is it the causation? Saying it can't be proved doesn't disprove a causation, such is merely an admission we don't know.
Should we use mercury in vaccines? If arsenic was found to be a good substitute, should we use arsenic-based perservative in vaccines?
Now where did that statement come from? Due you mean the large number of babies that are birthed in this country by third world illegal women, who came to this country already with child and probably were never vaccinated for anything. Sort of makes you wonder doesn't it????