Nearly one in five American women ends her childbearing years without having borne a child, compared with one in ten in the 1970s, the Pew Research Centre reports. Practically the only group of women less likely to be childless now compared with about two decades ago are those with advanced degrees.

No-one will be surprised at the new statistics, based on Census figures for 2006 and 2008, as they confirm everyday observations in many countries.

Compared with other developed nations, childless rates in the United States are on par with some nations and higher than others, according to data compiled by the Organisation for Economic Co-operation and Development. Among women born in 1960, 17% in the U.S. were childless at approximately age 40, compared with 22% in the United Kingdom, 19% in Finland and the Netherlands, and 17% in Italy and Ireland.

Higher education is the factor most likely to predict a childless career, but not to the same extent as formerly. In 1992-94 women with advanced degrees were much more likely to be childless, but their rate has declined so that all women with degrees now have a childlessness rate of around 23 to 25 per cent in their early forties. The most dramatic increase in childlessness has been among women with less than a high school diploma.

Being unmarried has less and less to do with whether a woman has children. Among 40 to 44-year-olds ever married, 13 per cent had no children of their own in 2008 — up from 11 per cent in 1994. But with 40 per cent of births now to never-married women, childlessness in this group has declined from 71 per cent in 1994 to 56 per cent in 2008.

The study did not look at women with step-children or adopted children.

How much of the increase in childlessness is voluntary, and how much the result of factors such as career building, economic circumstances and delay? According to the study,

Among older women, ages 40-44, there are equal numbers of women who are childless by choice and those who would like children but cannot have them, according to an analysis of data from the National Survey of Family Growth.3 In 2002, among women ages 40-44, 6% were deemed voluntarily childless, 6% involuntarily childless and 2% childless but hoping to have children in the future.

But attitudes to children have also changed. Marriage, when it occurs, has become less child-centred and more focused on the couple’s relationship. In a 2007 Pew study 41 per cent of adults said that children are very important for a successful marriage, compared with 65 per cent who said so in 1990.

As for the impact on society, attitudes are more mixed. About half the public — 46% in a 2009 Pew Research Center poll — say it makes no difference one way or the other that a growing share of women do not ever have children. Still, a notable share of Americans — 38% in that 2009 survey — say this trend is bad for society, an increase from 29% in a 2007 Pew Research survey.

Bad it may be, but surprising it is not. The contraceptive culture in which today’s 40-somethings have grown up is all about delaying childbearing until some imagined optimum time — a moment that, for an increasing number of women, never comes, or comes when their fertility is all but spent.

This is a difficult knot to untie because so much else in society has been affected by it — the labour market, housing, relationships between men and women, attitudes to marriage and children… I am looking forward to the study that shows how younger adults who are bucking these trends are getting on.

Carolyn Moynihan

Carolyn Moynihan is the former deputy editor of MercatorNet