Autism is a developmental disorder characterized by troubles with social interaction and communication and by 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. Autism affects information processing in the brain by altering how nerve cells and their synapses connect and organize. Early speech or behavioral interventions can help children with autism gain self-care, social skills and communication skills. An autistic culture has developed, with some individuals seeking a cure and others believing autism should be accepted as a difference and not treated as a disorder. Globally, the prevalence of autism in the Iran has risen steadily since researchers first began tracking it in 2000.