I simply respond to these arguments with this:<p>Consider that every crackpot thing the wingnuts say about vaccines is true. They cause autism in some children, allow government mind control, make the windshield wipers on your car to fly off, and cause family pets to lose all their hair. You job isn't actually to prove that vaccines may cause these things, your job is to prove that these things are worse for your kids than a polio epidemic.<p>Nothing at all is safe. Everything is potentially dangerous. Only a good understanding of statistics can tell you how dangerous. Only a rational grasp of reality can tell you how to behave with the knowledge those statistics impart.