Dads of newborns are older than ever according to a new study. Research into birth data published in the journal Human Reproduction has revealed that the average age for the dad of a newborn increased 3.5 years over the last four decades, placing the typical new American dad over the age of 30 for the first time. But The implications go beyond the fact that 40-year-olds with achy knees will soon be attempting to keep up with 10-year-old offspring.
“The longer that the couple waits, that necessarily means less number of children,” lead study author and Assistant Professor of Urology at Stanford Dr. Michael Eisenberg told Fatherly. “I think that will be reflected in the birth rate. There is just going to be fewer children born. That could be good. It could be bad.”
Eisenberg and his team were motivated to fill in data gaps in fatherhood age statistics. While maternal age is well documented by federal agencies like the Centers for Disease Control for purposes of tracking maternal health outcomes, fatherhood age is rarely collected. In order to do so, researchers turned to the National Vital Statistics System in order to parse data on 168,867,480 births between 1972 and 2015. The team not only looked at a newborn father’s age but also ethnicity and educational attainment.
The data revealed that since the early 70s a newborn’s father’s age has crept up a little over three years. Where it was once around 27-years-old, the average age for typical modern fathers is now 30.9-years old. That said, the number of fathers older than 30 also increased. For instance, father’s over 40 represent 8.9 percent of dads of newborns, more than double the 70s share of 4.1 percent. Unexpectedly, the trend was consistent nationwide, across all levels of education and ethnicity.
Another aspect of the finding researchers did not expect was the trend of mean paternal age difference, or the father’s age minus the mother’s age, representing the difference in ages between the two. “I thought that maybe over time the gap would be widening,” Eisenberg says. He understood that current data shows that mothers are getting older, but expected if anything average fatherhood age would be on a similar same trajectory. “But we actually showed that the gap is narrowing. This shows that mother are beginning to get older at a faster clip.”
Eisenberg suggests that narrowing gap could be due to improvements in birth control, better assisted reproductive therapies and even a desire from both parents to be better established in career prior to having children. And given all of that, he uncertain if there will be any kind of eventual age ceiling.
“Certainly there’s a biological limit as to what we can do,” Eisenberg explains. “And it’s possible that at some point we will see some plateauing, although in this data we didn’t necessarily see that.”
The takeaway for dads looking to become fathers or who are new, older dads, is that the definition of what an older dad seems to be a moving target. So there’s really no need to worry about the possibility of becoming a dad, “too late.”
“There’s lots of benefits to waiting a little bit to have a child,” Eisenberg says. “It’s not all negative.”