While anxious parents wait, researchers hope they're a step closer to answers about the possible link between vaccines and the devastating condition of autism.

Autism is a heartbreaking brain disorder that's on the rise in the US. While no one knows the cause, many parents suspect childhood vaccinations play a role.

Now a national panel of experts just completed another round in the struggle to find answers.

We first visited Robert three years ago. His mother, Ricci King, noticed the early, disturbing signs of autism when he was a toddler.

"He has limited ability to communicate with us. It's a struggle for him," said King.

Ricci suspects a link to his childhood vaccinations.

Until 1999, the vaccines were routinely made with a mercury preservative called Thimerosal.

"Mercury is one of the most poisonous substances that we know," said King.

Scientists disagree on a link between vaccines and autism. While some studies suggest there's no connection, one report just out concludes mercury may interfere with brain activity in a way that could cause autism.

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"It was done on cells in laboratories, and we're a long way from showing that's actually the way it works in humans," said Dr. Alfred Berg of the University of Washington.

Dr. Berg returned Wednesday from his ninth meeting of a national panel of experts. They're evaluating the research to hopefully give parents answers about vaccines' connection to autism.

Berg says the panel has already looked at the connections between vaccines and a variety of outcomes.

"I find the evidence for the most part reassuring that in most cases the evidence favors no association between vaccine and an adverse outcome," said Berg.

But regarding autism, Dr. Berg says he and others on the panel convened by the Institute of Medicine have not reached any conclusions. They are taking comments from the public until February 16th, and their final report is not expected until this summer.

Still, Ricci King is doubtful the panel will bring her and other parents closer to the answers they need.

"What will resolve the issues for parents is to see adequate funding directed toward the cause of autism how to treat it. How we as parents and families are to support our children for you know, a lifetime," said King.