POCKET LIVING has been building and selling small flats in London since 2005. The flats have many of the things that young, single people want, such as bicycle storage, and lack the things they do not, such as large kitchens and lots of bookshelves. At first, Pocket expected that most buyers would be in their late 20s, says Marc Vlessing, the firm’s boss. Instead the average age is 32, and rising. It is not that many buyers are yet to have children, speculates Mr Vlessing; rather, they probably will never have them.

A growing number of city-dwelling Europeans are in the same situation. Just 9% of English and Welsh women born in 1946 had no children. For the cohort born in 1970—who, barring a few late surprises, can be assumed to be done with babies—the proportion is 17%. In Germany 22% of women reach their early 40s without children; in Hamburg 32% do.

All of which might seem to suggest that Europe is bent on self-erasure. Childlessness is “a symptom of a feeble and terminally ill culture” that has lost touch with its heritage, according to Iben Thranholm, a conservative Danish journalist. The suggestion is misleading, however. Mass childlessness is not a sign of demographic collapse, nor is it remotely novel. It would be more accurate to say that rich countries are updating a long tradition.

In some European countries, such as Germany and Italy, the overall birth rate is low and childlessness is common. But other countries, such as Britain and Ireland, combine a high birth rate (by European standards) with a high rate of childlessness. And in still other countries, especially formerly communist ones in eastern Europe, childlessness is rare but birth rates are low, because many women have one child. Overall, there is surprisingly little correlation between childlessness and fertility (see chart 1).

Many countries that have lots of childless women today had even higher rates in the early 20th century. Indeed, the baby-filled late 20th century looks like a blip (see chart 2). That reflects deep-rooted social norms. In pre-industrial western Europe, men and women did not marry while they were maids or apprentices, but only when they could set up households of their own. To stay unmarried and childless was a sign of economic failure. But it was not shameful in itself. “It is poverty only which makes celibacy contemptible,” explained the heroine of Jane Austen’s novel, “Emma”. The attitude lingers. In western Germany, people without children tend to feel only mild social stigma. “It’s something that requires an explanation, but not a lengthy one,” says Tanja Kinkel, a successful novelist who did not have children because she did not find a suitable partner. And western Germany combines a forgiving attitude to childlessness with a harsh view of working mothers. Until recently, nurseries were rare; a woman who put her child in one might be abused as a “Rabenmutter” (raven mother). Many happily working women simply opt out. Childlessness is becoming more common in countries like Italy and Spain, which also squeeze working mothers. But perhaps the best example is Japan. Even if Japanese mothers were not pressed to stop working (which they are) they would be pushed into it by a brutal office culture. In a Japanese firm everybody is responsible for everything, complains one woman, an architect who lives in Tokyo. As a result, nobody dares to leave work early, which makes parenthood almost impossible. She delayed having children and is undergoing fertility treatment at the age of 41. Japan’s childless rate has shot up from 11% for women born in 1953 to 27% for women born in 1970. The reasons why people do not have children are varied, complex and often overlapping. A few (but, pollsters find, not many) never wanted them. Others do not meet the right person. Some fall in love with people who already have children, and feel satisfied. Others suffer from medical problems. A great many fall into a group that Ann Berrington, a demographer at the University of Southampton, calls “perpetual postponers”. Waiting to start a family until they are finished with education, until they have a stable job and a house, they find it is too late.

Almost everywhere, the most educated women are least likely to have children. And the highest rates of childlessness are found among women who pursue degrees in non-vocational subjects. Researchers at Stockholm University have found that 33% of Swedish women born in the late 1950s who studied the social sciences did not have children, compared with 10% of primary-school teachers and just 6% of midwives. It may be that teaching and midwifery attract women who strongly desire children, or that these jobs offer more parent-friendly hours and conditions. But the difference is probably also down to job security. A trained teacher can expect to find a stable job at a younger age than a trained anthropologist can.

The charitable childless

Although childlessness makes some people utterly miserable, that is not the case for most. One multi-country study by two demographers, Rachel Margolis and Mikko Myrskyla, suggests that childless people aged 40 and over in formerly communist eastern Europe are a little unhappier than people with children, once you control for things like wealth and marital status. That might reflect the stigma against childlessness in those countries. In liberal Anglo-Saxon countries, though, middle-aged childless people appear to be slightly happier than parents. The same demographers find that young parents are gloomier than childless youngsters.

Amazing as it may seem to parents who spend their evenings and weekends traipsing to football training and piano lessons, childless people find plenty of things to do with their time. Among these are good works. One German study found that 42% of charitable foundations were created by childless people. Ms Kinkel started a charity called Bread and Books, which operates mostly in Africa. She describes it as her way of nurturing the next generation.

People without children are far more likely to bequeath money to charity, points out Russell James, an expert on philanthropy at Texas Tech University. In 2014 fully 48% of married childless people aged at least 55 who had written wills or will-like documents committed to giving something to charity. That was true of only 12% of parents and a mere 8% of grandparents. Knowing this, American universities have become acutely interested in whether their alumni have offspring, says Mr James.

That question is easier to answer for women than for men. Men’s fertility declines with age, but less predictably than women’s fertility. So, whereas demographers and fundraisers can reasonably assume that a 45-year-old woman will have no more children, they cannot assume the same for a man. Worse, men sometimes forget their children when filling in census forms—and may have fathered children they do not know about. Still, two things are clear. Childless men are numerous, and quite different from childless women.

Men are erratic. Some are reproductive prodigies, having many children with more than one partner. Others—more than is the case for women—have none at all. Ms Berrington finds that 22% of British men born in 1958 were childless at the age of 46, compared with 16% of women. And in many countries childless men are disproportionately working class. French men who have never worked are about twice as likely to have no children as men who hold good white-collar jobs. Michaela Kreyenfeld, a demographer at the Hertie School of Governance in Berlin, finds that 36% of west German men without university degrees born in the early 1970s were childless in their early 40s. Among men with degrees, the rate was 28%.

That suggests men and women end up childless for quite different reasons. Women often have no children because they have prioritised education or work in their 20s and 30s. Men are more likely to remain childless because women do not view them as good boyfriend material—let alone good husband or father material. “They have a problem finding partners,” suggests Ms Kreyenfeld.

The distinction might be disappearing, however. In western Germany, childlessness is rising among less educated women, who are converging with their highly educated peers. In Finland, a switch has already occurred: women with only a basic education are the most likely to remain childless. It may be that, as two-earner households become more common, men have taken to judging women as women have long judged men. Those who fail to land dependable jobs might not be given a good opportunity to have children.

Nobody knows whether childlessness will rise further. It has been going up in most European countries, but not all: the rate has fallen in Switzerland, for example. One possibility is that childlessness will veer up and down, mirroring the economic cycle. As the average age of marriage rises and couples push childbearing into their mid- or even late 30s, they become increasingly vulnerable to shocks. A bad recession or a mortgage-lending squeeze will encourage couples to pause—and, because many now give themselves only a narrow window before their fertility drops, some will be knocked out of childbearing altogether.