Researchers analyzed data from 9,000 adults, ages 26 to 31, who took part in a federal government survey in 2011. Among those who were parents and did not graduate from college, 74 percent of mothers and 70 percent of fathers had at least one child outside of marriage.
Among young adults with children, non-college graduates accounted for 81 percent of mothers and 87 percent of fathers.
Overall, 53 percent of the women in the study had at least one child, 64 percent had at least one child out of wedlock, and 47 percent had all of their babies when they weren't married.
The lower their levels of education, the more likely mothers were to have children outside of marriage. Rates of having at least one baby out of wedlock were: 32 percent for mothers with four or more years of college; 67 percent for those with one to three years of college; 71 percent for those with only a high school diploma, and 87 percent for those who did not finish high school.
Slightly more than one-third of the mothers in the study had babies while married, including almost half of whites, 28 percent of Hispanics and 10 percent of blacks, the Johns Hopkins University researchers said.
All of the figures were similar for men, according to the study presented at a recent Population Association of America meeting. Studies presented at meetings are generally viewed as preliminary until they've been published in a peer-reviewed journal.
"Clearly the role of marriage in fertility and family formation is now modest in early adulthood and the lofty place that marriage once held among the markers of adulthood is in serious question," study author and sociologist Andrew Cherlin said in a Hopkins news release. "It is now unusual for non-college graduates who have children in their teens and 20s to have all of them within marriage."
"If marriage retains its place anywhere, it would be among the college graduates, because most of them do not begin to have children until after they are married. The difference between them and the non-college-educated with regard to the percentage of births within marriage is so striking as to suggest a very different experience of early adulthood," Cherlin said.
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