Out-of-wedlock births rose to record levels in 2007, accounting for four-in-ten of all U.S. births that year, according to newly released preliminary data from the National Center for Health Statistics.

The share of births to unmarried women has been rising for decades, but the increase has accelerated since 2002. The number of out-of-wedlock births has gone up 26% since then. The new National Center for Health Statistics report indicates that all measures of births to unmarried women rose to historic highs in 2007 — the number of births (1.7 million), birth rate and proportion of births.

Most Americans say that the growing prevalence of births to unwed mothers is a problem for society, but responses are more mixed — and differ sharply by generation — on the question of whether it is always wrong for an unmarried woman to have a baby, according to a 2007 Pew Research Center Social & Demographic Trends survey.

In short, there is a stronger consensus in public opinion about the social cost of out-of-wedlock births than there is about the morality of these births.

In the Pew Research survey, two-thirds (66%) of all respondents said that more single women having children is a bad thing for society, and 59% said that more unmarried couples having children is a bad thing for society. These trends generated the most concern among a number of recent demographic changes related to marriage and parenting that respondents were asked to judge.

Responses are more mixed, however, on the question of whether unmarried women having children is wrong or not. A slight majority of Americans (52%) say it is wrong only sometimes (33%) or not wrong at all (19%). A quarter (26%) say it is always wrong and 18% say it is almost always wrong.

On the question of whether unmarried women having children is wrong, there are no differences by gender. But attitudes do differ by generation. Most people ages 18-49 say that births out of wedlock are wrong only sometimes or not at all. Americans ages 50-64 are evenly split on this question. And among Americans 65 and older, two-thirds say unmarried births are always or almost always wrong.

The Pew Research Center survey was conducted by telephone from February 16 through Match 14, 2007, among a randomly selected, nationally representative sample of 2,020 adults. It has a margin of sampling error of 3 percentage points.