Key Factors for Autism: A 40-year-old woman’s risk of having a child later diagnosed with autism is 50% greater than a woman between 25 and 29. Advanced paternal age was also associated with an elevated risk for autism even when the mother was younger.

For example, children fathered by a man older than 40 years were twice as likely to develop autism as those children with fathers between the ages of 25 and 29, among births to mothers younger than age 25. That association dissipated, however, among mothers older than 30 years.

Risk of autism connected to maternal age