More women are delaying marriage, but not necessarily delaying having children.

With 48% of first births now outside of marriage, "today's unmarried twentysomething moms are the new teen mothers," says a report released today by the National Marriage Project, the Relate Institute and the National Campaign to Prevent Teen and Unplanned Pregnancy. And that comes at a price to them and their children.

Among young women with high school diplomas, 58% of first births are now outside marriage, the report says. For high-school dropouts it's 83%; for college-educated women it's 12%. The report notes that 54% of young women are high school graduates; 37% are college graduates.

Overall, the median marriage age is now 27 for women, 29 for men. But the median age at which a woman has her first baby is 26, the report says.

Young people delay marriage to finish their educations, launch their work lives and try to achieve economic security. Marriage is "something they do after they have all their other ducks in a row," the report says. In general, the delay works out well for college-educated young people who also delay having children, it adds.

The report says reviving cultural support for earlier marriage may be part of the solution, but some experts question that approach.

The benefits of delayed marriage can include higher incomes for women and lower divorce rates, it notes. But there also are costs for young people, says Bradford Wilcox, the sociologist who directs the National Marriage Project. "The ones who are married have more life satisfaction."

For children, the cost can be instability, according to the report: 39% of young unmarried parents who start out living together break up before their child is 5 years old; just 13% of married parents split so soon. Such upheaval hurts children, many studies have found.

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