Do vaccines cause autism?
little girl getting a shot

Does that shot have any thimerosal? Maybe not. Autism advocacy groups have lobbied­ to remove the preservative from many vaccines.

Peter Dazeley/Getty Images

­As any new mom or dad can attest, parenthood is nerve-wracking. Before the baby is even born, the decisions start piling up, right next to that stack of unread paren­tal literature. Breast or bottle? Homecare or daycare? Vaccinate or not? With autism spectrum disorders (ASDs) on the rise, many parents are thinking long and hard about that last one. Why? Because some people believe that vaccines are causing ASDs, and they're vocal. Whether you heard Jenny McCarthy, Hannah Poling's family or public health officials weighing in on the issue, autism was big news in 2008.

The alleged culprit? Thimerosal, a mercury-containing vaccine preservative added to shots to prevent bacterial contamination. Pressured by the public, pharmaceutical companies have lowered or removed the preservative completely from many vaccines. In fact, you might have even gotten a flu shot free of thimerosal this year. But autism rates aren't dropping. And vaccine-preventable diseases like measles are on the rise, according to the Centers for Disease Control and Prevention. It looks like being a parent didn't get any easier in 2008. But you can read more about in Do vaccines cause autism? ­