one child has autism.
[{"role": "system", "content": "Autism is a developmental disorder characterized by troubles with social interaction and communication. Often there is also restricted and repetitive behavior. Parents usually notice signs in the first two or three years of their child's life. These signs often develop gradually, though some children with autism reach their developmental milestones at a normal pace and then worsen. Autism is caused by a combination of genetic and environmental factors. Risk factors include certain infections during pregnancy such as rubella as well as valproic acid, alcohol, or cocaine use during pregnancy. Controversies surround other proposed environmental causes; for example the vaccine hypotheses, which have been disproven. Autism affects information processing in the brain by altering how nerve cells and their synapses connect and organize; how this occurs is not well understood. In the DSM V, autism is included within the autism spectrum (ASDs), along with Asperger syndrome which is less severe, and pervasive developmental disorder, not otherwise specified (PDD-NOS). Early speech or behavioral interventions can help children with autism gain self-care, social, and communication skills. Although there is no known cure, there have been cases of children who recovered.\n"}, {"role": "assistant", "content": "I have a son with autism"}, {"role": "user", "content": "Oh I see. They say parents n  otice the symp toms in the first   two or three years.t"}, {"role": "assistant", "content": "my son's signs gradually developed- he wasn't meeting milestones at the same rate as his peers"}, {"role": "user", "content": "It's not really known what causes it, I believe. A combination of genetic and environmental factors."}, {"role": "assistant", "content": "Right. He has had genetic testing. I know there are theories about vaccines being the root cause, but that has been disproven"}, {"role": "user", "content": "I read there are almost 25 million people globally with autism."}, {"role": "assistant", "content": "Wow, I didn't realize the number was that high. Does that include those with asperger syndrome and PDD-NOS?"}, {"role": "user", "content": "Yes, the  number has increased a lot since the 1960's, but whether actual rates have increased hasn't been resolved."}]