Is autism contagious?

Autism is a significant medical condition, as I am sure you already understand. I would recommend that you discuss appropriate care for your daughter as well as this question with your child's pediatrician. To answer your question -- NO. Autism is not contagious in the traditional sense. It is not like the flu in which one can pass it to someone else by a cough (for example). That being said, your son is at an increased risk for autism compared to the general population. Autism is a pervasive neurodevelopmental disorder that affects the person's ability and skills for social interaction. We know that autism is not contagious from experience with children with autism. However, the exact cause of autism is not known. We do know that there are factors like the mom's age at conception that increase risk. We also know that the genetic factors play a role -- brothers and sisters of autism patient's are more likely to have autism. For these reasons, your son may be at increased risk for it than the general population. There are some possible other causes, like infectious virus or other environmental triggers -- but this is not thought to be a contagious. We simply do not know. Autism is not contagious. Talk to your pediatrician for more information.