Women have long referred to their ticking biological clock, but men should also be paying attention to Father Time when it comes to fathering. Children whose father was older when they were conceived face some higher risks according to a new study, saying that kids born to these middle-aged dads are more likely to have a number of mental health disorders.
A Swedish study used data from international research which collected data from 2.6 million people born between 1973-2001. The researchers estimated risk for mental health problems like bipolar disorder, autism, attention deficit hyperactivity disorder (ADHD) and trouble performing at school. Researchers compared siblings with the same parent set, but also looked at subjects’ cousins when developing risk models. Controls were put in place for extenuating conditions, such as parental income and education.
Their models showed that children born to dads age 45 and older faced some serious risks:
- Bipolar disorder was 24 times more likely to develop in kids with older dads compared to children born to dads in their early twenties
- Children of middle-aged fathers were 13 times more likely to develop ADHD
- The children faced a 3.5 times greater risk for autism; risk for children of parents in their early twenties is one in 300
- They were twice as likely to abuse substances or attempt suicide
- Kids of mid-life fathers were two times more at risk for schizophrenia
- The children faced a 59 percent greater risk of low academic achievement
- They were 70 percent more apt to drop out of school entirely
The study is the largest and most rigorous on the subject performed so far, and its findings have pretty much rocked the research community. Few, if any, expected to see such strong age-related outcomes. There has been some idea of paternal age having an influence on children’s psychiatric health, but nowhere near what this new study suggests. By comparison, prior research had set many of these risk factors far lower, and even contravened some of the findings. Previous studies, for example, suggested that older paternal age actually lowered a child’s risk for substance abuse, suicide attempt or ADHD.
One reason that paternal age has gotten such little attention up until now has to do with the biology of male and female reproduction. Women are born with all their eggs. Those eggs degrade with the passing years, meaning that chromosome abnormalities are more likely over time.
Sperm, on the other hand, are not as old as the man as sperm cells reproduce. One scientist described sperm as copies made of copies. It appears that later copies are prone to error due to mutations in the genes accumulating. Scientists say that the bulk of those mutations are negligible, but some lead to psychiatric problems.
The report made a splash because so many couples are deciding to have children later in life. There are certainly benefits to postponing parenthood. Older parents tend to be more financially secure and have had time to pursue interests and education. On the other hand, putting off a family for too many years does appear to push up the risk factor for the children born to older parents.
It’s important to emphasize that the study does not indicate that all children born to older fathers will necessarily face these problems. The majority of children born to fathers in their 40s will be as healthy as all the rest. The risks go up with age, but that is different than saying something is a certainty. Still, the concept of a male biological clock is at least cause for further study.