By Amy Norton
WEDNESDAY, Aug. 30, 2017 (HealthDay News) -- New dads may sport a few more gray hairs than in years past, a U.S. study finds.
The average age of new fathers has risen in recent decades, research shows, raising questions about the possible social and public health impact.
The study, which analyzed federal birth records, found that fathers of newborns are now 3.5 years older, on average, than their counterparts in the early 1970s.
And the percentage of births to fathers older than 40 has more than doubled -- from about 4 percent in 1972, to 9 percent in 2015.
The pattern is not surprising, since it parallels what's been seen among U.S. women.
But much less research has explored the changing demographics of American fathers, according to senior researcher Dr. Michael Eisenberg.
"I think it's important for us to pay attention to these demographic shifts and what their implications could be for society," said Eisenberg, an assistant professor of urology at Stanford University in California.
On one hand, he said, older fathers are more likely to have kids affected by certain health conditions, such as