Traditionally, research has focused on women’s “biological clock.”

But in recent years, scientists have been looking more and more at how the father’s age at conception might affect the baby, too.

A study published Wednesday hints that age really might matter — in terms of the child’s mental health.

Researchers from the University of Indiana and the Karolinska Institute found that compared with children fathered by men who were 20-24 years old, kids born to dads who were 45 or older were three times as likely to have autism and 13 times as likely to have ADHD.

Kids born to older dads were also more likely to go on to develop substance abuse problems and get lower grades in schools. The findings appear in JAMA Psychiatry.

Read the full article at NPR.