A new U.S. Census Bureau survey finds that college graduates are less likely to marry before age 34 and less likely to have children at all.

The study shows that for each additional year a person spends in higher education, their chances of marrying before 34 drop by about 4%. Those who do marry are more likely to wed another college graduate.

Researchers also found that higher education correlates with lower birth rates, with many graduates choosing to delay or forgo having children.