Autism is a developmental disorder characterized by severe impairment in the ability to socialize and communicate with other people. Most people who have the condition are diagnosed around the age of 3 or 4 when they fail to develop normal social and communication skills.
Several studies have shown autism runs in families, leading researchers to believe the disease has a genetic basis. Others have suggested a role for obstetric complications. Researchers studied the medical records for children born with autism between 1980 and 1995, comparing them with their siblings and children from the general population who did not have autism.
Results showed autistic children were more likely to have older parents and to be a firstborn child. Their mothers also had a greater incidence of threatened abortion, epidural anesthesia use, induced labor, and a labor lasting less than one hour. Autistic children were more likely to have experienced fetal distress, have low scores on a standard test to measure functioning in newborns, and have been delivered via cesarean section.
Researchers conclude saying that the above observed complications are generally nonspecific and cannot predict autism development however they feel that their research supports the hypothesis that the development of autism ... is dependent on the genotype, and the presence of complications can be explained by a compromised prenatal experience for that genotype.