Vaccines and Autism

In everything I read or see on t.v. about Autism, they always mention how vaccines are the cause. My sister is another big believer in this. Although it's not proven, researchers say that the Mercury found in almost all vaccines is what eventually leads to slow developing of the brain. This, they also say, is the cause of other disorders like Aspergers disease, which is really simular to Autism. Crazy to think how something that is supposed to cause prevention and do well for a child could cause such harm. As I get older, I want to learn more about this, because I have also heard that Autism is genitic; that both the father and the mother had what it took to cause it. But, this believe is becoming more and more popular. Jenny McCarthy has written about vaccines in all of her books that she has written about Autism.  "If the vaccine companies are not listening to us, it's their fault that the diseases are coming back. If you give us a safe vaccine, we'll use it. It shouldn't be polio versus autism."