Children born to older fathers appear to be at higher risk of developing autism than those born to fathers in their 20s and 30s, according to a study of thousands of Israeli families.
The study was published in the September issue of the journal Archives of General Psychiatry, a publication of the American Medical Association. The researchers tracked 318,508 children born over six consecutive years where the father’s age at the child’s birth was known. For 132,271 of those children, the age of the mother was known as well.
Israel was used as the basis of the study because almost all of the boys, and three-quarters of the girls, in the study had to undergo health assessments prior to mandatory military service.
The study found that, even controlling for the age of the mother and other variables, children of fathers who were older than 50 at the time of conception had a risk of 52 in 10,000 of developing autism, a developmental disorder characterized by social withdrawal and repetitive behaviors.
That compares with risk rates of six in 10,000 for children of fathers who were 15 to 29 years old, and nine in 10,000 for children of fathers in their 30s. Children of fathers in their 40s had a risk rate of 32 in 10,000.
The study concluded that its results were the first “convincing” evidence that advancing parental age is a risk factor for development of autism.
“We really welcome the study,” said Marguerite Colston, the director of communications for the Autism Society of America in Bethesda, Md. “I think what makes this study different is the [large] size of the sample.”
A version of this article appeared in the September 13, 2006 edition of Education Week