More Bad News for Older Dads: Higher Risk of Kids With Mental Illness

For so long, mothers – particularly older moms — bore the brunt of responsibility for genetic disorders in their children. And for good reason. Eggs are stockpiled from birth, not made anew with each monthly reproductive cycle, so eggs stored for decades until childbearing can develop genetic mutations. The older the mother, the greater the chance of abnormalities that can contribute to conditions such as Down syndrome, especially after age 35. Fathers, on the other hand, constantly make sperm, so their reproductive contribution was supposed to be fresher and free of accumulated DNA damage. That may not actually be the case, however, according to the latest study in JAMA Psychiatry investigating how advanced paternal age can affect rates of mental illness and school performance in children. After a groundbreaking genetic analysis in 2012 highlighted the surprising number of spontaneous mutations that can occur in the sperm of older men, scientists have been delving into the relationship to better quantify and describe the risk. While some studies confirmed the connection, others failed to find a link. MORE: Older Fathers Linked to Kids’ Autism and Schizophrenia Risk In the latest research, Brian D’Onofrio, associate professor of psychological and brain sciences at Indiana University, and his colleagues attempted to address one of the biggest problems with studying the trend. Most of the previous investigations compared younger fathers and their children to different older fathers and their offspring. “That’s comparing apples and oranges,” says D’Onofrio. “We know young fathers and old fathers vary on many things.” So his team turned to birth registry data from Sweden and compared children born to the same fathers, evaluating the siblings on various mental health and academic measures. The study included 2.6 million children born to 1.4 million fathers. What they found surprised them – so much so that they spent about two months re-evaluating the data to make sure their numbers were correct. While the previous genetic study found that an older father’s DNA may account for about 15% of autism cases, D’Onofrio’s group found that the