The difference in when women start families cuts along many of the same lines that divide the country in other ways, and the biggest one is
education. Women with college degrees have children an average of seven years later than those without — and often use the years in between to finish school and build their careers and incomes.
People with a higher socioeconomic status “just have more potential things they could do instead of being a parent, like going to college or grad school and having a fulfilling career,” said Heather Rackin, a sociologist at Louisiana State University who studies fertility. “Lower-socioeconomic-status people might not have as many opportunity costs — and motherhood has these benefits of emotional fulfillment, status in their community and a path to becoming an adult.”