There is abundant evidence that autism occurs in families with evidence of autoimmunity. There is also evidence that mothers of an autistic child may have antibodies that react with brain tissue and even evidence that these antibodies, when given to pregnant mice or pregnant monkeys, cause behaviors in the offspring analogous to aspects of the autistic syndrome. The investigators will explore the role of maternal antibodies in ASD, identifying maternal sera with anti-brain antibodies, determining if these antibodies can cause brain pathology and neurologic abnormalities in mice exposed to them during pregnancy, characterizing the brain antigen(s) recognized by the antibodies and assessing how frequently these antibodies are present in mothers of an autistic child. This group will also examine children born to mothers with particular maternal antibodies examine the relationship between these circulating antibodies and autism behaviors in the children. What this means for people with autism: While the investigators are aware that this mechanism of disease may be operative in only a subset of patients, these experiments can determine the validity of this model. These studies may then help identify at-risk pregnancies for future studies of prevention in appropriate individuals. Furthermore, they may help identify the brain injuries, that caused by maternal antibody or by other mechanisms lead to autism.