Having kids
Today the average woman gives birth to her first child at the age of 25, up from 23 in 1980 and 21 in 1970.

The fact that more women are going to college is certainly part of the equation. But the economy is also causing more young people to put off having kids.

The cost of child care alone has risen far faster than inflation, while at the same time, more families rely on two incomes simply to get by. That forces young families with two working parents to face a difficult tradeoff: Either pay for expensive child care or give up the income of one parent so he or she can stay home with the kids.

At about $16,000 a year, the average cost of day care for two children -- one infant and one pre-schooler -- now exceeds the median rent in all 50 states.

"It costs a lot of money to raise a child," Draut said. "When everybody's economic situation is so tenuous and fragile, it makes sense that people would deliberate even more and delay starting a family even longer."

In 2010, more than one in three young families lived in poverty, the highest share on record.

Text by Annalyn Censky, Charts by Liz Starin @CNNMoney - Last updated December 13 2011: 5:49 AM ET
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