A pair of new studies suggest that a child’s odds of developing autism could be impacted by the experiences of their parents and grandparents.

Researchers say they’ve identified a higher risk of autism among children born to women who were abused as youngsters. Meanwhile, findings from a separate study indicate that men who are older when their children are born are more likely to have grandchildren with the developmental disorder.

The studies, both published online this month in the journal JAMA Psychiatry, offer a new avenue of exploration in the hunt to understand what underlies autism by looking to patterns in previous generations in addition to the current one, researchers say.

To examine the influence of abuse, researchers looked at data from more than 50,000 women, finding that those who experienced physical, emotional, or sexual abuse as children were as much as three-and-a-half times more likely to give birth to a child with autism. What’s more, the risk level appeared to increase with the severity of abuse, the study found.

“Our study identifies a completely new risk factor for autism,” said Andrea Roberts, a research associate at the Harvard School of Public Health who led the study. “Further research to understand how a woman’s experience of abuse is associated with autism in her children may help us better understand the causes of autism and identify preventable risk factors.”

Beyond the experiences of a child’s parents, however, an international group of researchers reports that grandparents can also influence autism odds.

Findings from an examination of data on nearly 40,000 people born in Sweden since 1932 suggest that men who were age 50-plus when their child was born are over one-and-a-half times more likely to have a grandchild with autism as compared to men who had kids when they were ages 20 to 24.

“We know from previous studies that older paternal age is a risk factor for autism. This study goes beyond that and suggests that older grandpaternal age is also a risk factor for autism, suggesting that risk factors for autism can build up through generations,” said Emma Frans of the Karolinska Institutet in Sweden who led the study.

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