zebra the epidemeological studies will never prove a link. These type of studies are incredibly weak at trying to find a problem of this type (remember it is likely that only approx 10% of autism is caused by MMr- numbers are small). Personally I think some of the best evidence is coming out of the Autism Research Unit. They are quite careful in their claims, but I have noticed they are getting more confident as they are getting more data. Also the research finding vaccine strain mealses in the brain is farily compelling evidence (and enough to challenege the manufacturers in court)
FWIW autism is an autioimmune disorder. Autistic kids have notorioulsy bizarre immune systmes. Family histories are generally full of autoimmune conditions. Is it so unlikely that given a genetic predisposition for autism that vaccinations are going to be a bit risky for these kids? Could be MMR that triggers could be something else. Quite frankly though the parents that I know that blame the MMR tell a totally different story to those of us that don't (and I do blame certain immune assualts but won;t go into that). The arrogance of the medical profession in ignoring this is incredible. Mind you I've tried to explain things about my son to the paediatricians and specch and language therapists etc and it it like talking to a brick wall. It doesn't surprise me- they see what thy want to see.
I would say thet the risk MMR poses to any individual child is small. if your child has never shown any sign of allergy, and there is no autoimmune disease in your family (no type I diabetes, MS, arthritis, crohn etc etc) then the risk is probably negligble. If there is then read everything (reliable) that you can lay your hand on. If you read the original research (including the epidemeological studies) then it talks for itself really. Read Paul Shattock's research and try to catch him on the radio- he works on the ground a lot so to speak.
Another person who has worked a lot in the area is Dr Natacha Campbell McBride. She works in Cambridge and is a nutritionist for children with learning diasbilities. She is medically qualified and also hold postgrad degree in neorology. I've read her views on the role of vaccinations in the devlopment of autism in the Autism File. I found this article particularly interesting as her possible route to autism decribes exactly what I believe happened to my son. (I amlmost passed out when I read it- it was what I had been saying for the previous year- there in black and white).
So in summary- read all the reserch you can. Don't read press reports (they're often inaccurate)- read the research, or articles written by the researchers themsleves. If I sound stroppy about this -yes I am. I have no idea whether MMR can cause a link, but I do know what living with autism is like and the consequences if it does, and whilst the jury is out the vaccinations should be as well.