Dad's age didn't matter unless father was older, mom much younger, study found
MONDAY, Feb. 8 (HealthDay News) -- Older moms are more likely to have a child with autism than women who give birth at a younger age, new research shows.
Researchers from University of California, Davis, looked at records for the nearly 5 million births in California between 1990 and 1999, a decade in which autism incidence increased 600 percent statewide.
A woman's risk of having a child diagnosed with autism rose by 18 percent for each five-year increment in her age, according to the study. That means that a woman who gave birth at age 40 or older had a more than 50 percent greater chance of having a child with autism than a woman who gave birth between 25 and 29, and a 77 percent greater chance of having an autistic child than a woman who gave birth before the age of 25.
While previous research has shown that older dads are more likely to have a child with autism, this study found no such link between autism and paternal age, with one exception -- older men who had children with much younger women.
Men over 40 who had a child with a woman under 30 had a nearly 60 percent increased risk of having a child diagnosed with autism compared to men aged 25 to 29 who fathered a child with a young woman.
Among mothers over 30, the increased risk associated with having a baby with a man older than 40 dissipated, according to the study in the Feb. 8 online issue of the journal Autism Research.
In California, women having babies over age 40 increased by 300 percent between 1982 and 2004, the researchers noted. Still, they stressed that the rise in women over 40 having babies probably accounted for less than 5 percent of the statewide surge in autism cases noted in 1990s.
"Advancing maternal age is contributing only a very small proportion of the increase in autism cases," said study author Janie Shel
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