One reason for the increase, said demographers and sociologists who study families, is that people are marrying later in life, after they have completed their education.

根据家庭研究的人口统计学者和社会学者的说法，这种增长的一个原因是现在人们结婚较晚，在完成学业之后才结婚。

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Data from the Centers for Disease Control and Prevention show the number of couples starting families later in life continues to rise.

美国疾病控制和预防中心(Centers for Disease Control and Prevention)的数据显示，晚育夫妇数量继续上升。

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Professor Richard Fleming, director of the Glasgow Centre for Reproductive Medicine, said that the root cause was because women were starting their families later in life.

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Women in the Northeast who married and started families later in life tended to vote Democrat while their Midwestern peers who got a head start on marriage and family building often voted Republican, Belgian demographer Ron Lesthaeghe found.

CNN: STORY HIGHLIGHTS

Life is slowing down and speeding up at the same time: families arrive later, even as careers are accelerating.

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