You only have yourself to blame for a failing grade — unless, of course, your dad was pushing 50 when you were born. Then it might be his fault.

That is the conclusion of a new study from Indiana University and the Karolinska Institutet in Stockholm, where researchers have determined that advancing paternal age at childbearing is tied to lower academic performance and overall educational achievement. What’s worse, children of older fathers are also at much greater risk of psychiatric issues. Dr. Brian D’Onofrio, an associate professor at Indiana University and lead author of the new study, said in a press release that his team was "shocked" by the findings.

"The specific associations with paternal age were much, much larger than in previous studies,” he explained. "In fact, we found that advancing paternal age was associated with greater risk for several problems, such as ADHD, suicide attempts and substance use problems, whereas traditional research designs suggested advancing paternal age may have diminished the rate at which these problems occur."

The study, which is published in the journal JAMA Psychiatry, surveyed an immense sample: Everyone born in Sweden between 1973 and 2001. D’Onofrio and colleagues compared paternal age with psychiatric disorders and academic issues like ADHD, bipolar disorder, failing grades, low level of education, and low IQ scores. They also looked at substance abuse and suicide attempts.

They found that, compared to a child born to a 24-year-old father, a child born to 45-year-old father was twice as likely to have a psychotic disorder, 3.5 times more likely to have autism, and 25 times more likely to have bipolar disorder. In addition, these children were more than twice as likely to have suicidal behavior and develop drug problems. The team controlled for other factors by analyzing data from older siblings raised in the same household.

Older Fathers

According to D’Onofrio, the study’s methodology allowed for unprecedented level detail.  "First, we had the largest sample size for a study on paternal age,” he explained. “Second, we predicted numerous psychiatric and academic problems that are associated with significant impairment. Finally, we were able to estimate the association between paternal age at childbearing and these problems while comparing differentially exposed siblings, as well as cousins.”

The study adds to the growing number of efforts to quantify the influence of advancing parental age on children. Another example is a study from last year, in which researchers from the University of Dublin show that women who give birth outside the optimal fertility period — that is, between the ages 20 and 34 — are significantly more likely have pregnancy complications.

On the flip side, children born to older dads also live longer and have “stronger DNA,” according to a 2012 study from Northwestern University.

"While the findings do not indicate that every child born to an older father will have these problems, they add to a growing body of research indicating that advancing paternal age is associated with increased risk for serious problems,” D’Onofrio told reporters. “As such, the entire body of research can help to inform individuals in their personal and medical decision-making."

 

Source: D’Onofrio B, et al. Parental Age at Childbearing and Offspring Psychiatric and Academic Morbidity. JAMA Psychiatry. 2014.