Autism risk linked to both parents’ ages

A new 10-year study, which analyzed nearly 5 million births in California, has found autism risk linked to both parents’ ages.

While mother’s age has long been linked to higher odds of her child’s risk of autism, the findings of the current study concluded that the father's age is also a contributing factor when the mother is young.

The findings of the study feature in the Feb. 8 online advance issue of the journal Autism Research.

Details of the study
The study by a team at the University of California Davis analyzed 4.9 million births (singleton) and 12,159 autism cases in California between 1990 and 1999.

For a woman aged over 40, the risk of having a child with autism was 51 percent higher than the risk her younger counterpart aged between 25 and 29 faced, researchers found.

The risk soared with age, making a 40+ woman 77 percent more likely than women under age 25 to have a child with autism, researchers highlighted.

Every five-year increase in the age of the mother raised her risk of having a child with autism by 18 percent, the research team revealed.

Also, being an older father, 40 or older, also contributes significantly to autism risk if the mother is under 30, they found.

The findings suggested that when the parental age is over 40 and the maternal age is under 30, the risk of having an autistic child is 59 percent greater than for younger men with under 30 partners.

"It’s important we not turn around and blame mothers," Dr. Dolores Malaspina, a psychiatrist at New York University Langone Medical Center said. "The evidence is very, very strong that there is a paternal age effect."

But the study does not conclude that mother’s or father’s advanced age causes autism. Instead, it conveys that age is ‘one risk factor among many factors that contribute.’

"In the majority of cases, we are not going to find that any one factor accounts for any individual child's autism. Parental age is just one risk factor that is interacting with other genetic and environmental factors that lead to a child developing autism," notes Geraldine Dawson, chief science officer for Autism Speaks, a group that advocates for autism research.