A hit on PubMed that looks interesting, titled 'Mercury and autism: accelerating evidence?' Unfortunately I don't have access to more than the abstract.
According to the abstract (authored by Mutter J, Naumann J, Schneider R, Walach H and Haley B at the Institute for Environmental Medicine and Hospital Epidemiology, University Hospital Freiburg, Germany), the links between mercury exposure and autism are real.
The abstract notes: 'Recently, it was found that autistic children had a higher mercury exposure during pregnancy due to maternal dental amalgam and thimerosal-containing immunoglobulin shots.' Furthermore, 'In vitro, mercury and thimerosal in levels found several days after vaccination inhibit methionine synthetase (MS) by 50%. Normal function of MS is crucial in biochemical steps necessary for brain development, attention and production of glutathione, an important antioxidative and detoxifying agent. Repetitive doses of thimerosal leads to neurobehavioral deteriorations in autoimmune susceptible mice, increased oxidative stress and decreased intracellular levels of glutathione in vitro. [...] Promising treatments of autism involve detoxification of mercury, and supplementation of deficient metabolites.'
It's interesting to read the point about neurobehavioural deterioration in 'autoimmune susceptible mice'. There are a few autoimmune issues in my family history (for instance eczema and allergies). But you have to look at the most recent generation to find any autism.
Something causes autism.