Children born to fathers who are age 40 or older have an increased risk of developing autism, a new study suggests.
Autism is marked by poor verbal skills, repetitive behavior patterns, and social detachment. It shows a hereditary component; someone with an autistic sibling has an increased risk of being autistic. But no single gene mutation or alteration appears to explain most cases of the disease. "There are probably many genes that might contribute to it," says Abraham Reichenberg, a neuropsychologist at Mount Sinai School of Medicine in New York City.
The incidence of autism rose roughly tenfold in the United States between 1975 and 1995. While some of the increase might have resulted from greater awareness and diagnosis of the condition, scientists have sought other explanations. Some have focused on paternal age, which appears to be increasing in industrialized countries.