Over roughly the past four decades, the average age of U.S. fathers at the time of their child's birth increased by 3.5 years, from 27.4 years in 1972 to 30.9 years in 2015, according to the study.
Over roughly the past four decades, the average age of U.S. fathers at the time of their child's birth increased by 3.5 years, from 27.4 years in 1972 to 30.9 years in 2015, according to the study.