The risk of autism in offspring increases rapidly after the potential mother's age crosses 30 years and also with the father's increasing age, says a new study.
Researchers from the Drexel University School of Public Health in Philadelphia and Karolinska Institute in Sweden analyzed records of 417,303 children born in Sweden between 1984 and 2003 from a large population registry.
They revealed that the impact of parents' age on autism risk in offspring is varied. Older mothers appear to have a greater influence on a child's autism risk rather than older fathers, the study indicated. The risk of autism was very low in kids born to women below the age of 30.
"The open question at hand really is, what biological mechanisms underlie these age effects?" said the study's lead author, Dr Brian Lee, of Drexel University in Philadelphia. "The absolute risk of having a child with ASD is still approximately one in 100 in the overall sample, and less than two in 100 even for mothers up to age 45."
The study details are published in the International Journal of Epidemiology.