When children appear to develop normally in their early years and then start to show symptoms of autism -- a condition known as regressive autism -- some parents have blamed vaccines .
Vaccination schedules happen close to the time children begin to show developmental changes .
When children appear to develop normally in their early years and then start to show symptoms of autism -- a condition known as regressive autism -- some parents have blamed vaccines because vaccination schedules happen close to the time children begin to show developmental changes .