THE French city of Rennes serves plates of asparagus tips to 18-month-old tots. Toulouse treats its under-fives to Roquefort-cheese tart. Toddlers in Amiens are offered a camembert tartiflette as a starter. At the country’s state-run crèches and nursery schools, a four-course meal—cheese included—is standard fare. The French like to educate taste buds as well as minds. With a long history of pro-natalist policy, they also like to support working parents. Good catering, along with long opening hours and well-equipped public nurseries, are all part of the appeal.

Yet despite all the French do to support child-rearing, the country’s birth rate has suddenly gone into decline. In 2017, for the third consecutive year, the number of births in France dropped, and to its lowest level in two decades (see chart). Along with a slight increase in the number of deaths, the gap between births and deaths—which demographers call the natural increase—fell to its lowest point since the 1950s.

This is due not just to a decline in the number of French women of child-bearing age, although those numbers have indeed dipped over the past decade. It is also because French women are having fewer children. France and Ireland used to stand out as the two European countries in which women had, on average, close to the 2.1 offspring needed to hit the population replacement rate. Last year, however, the number of babies French women are expected to have in their lifetimes dropped to 1.88, its lowest level in almost 20 years.

Why have the French gone off babies? The answer is not just tougher economic times. Unusually among European countries, the French birth rate remained fairly stable through the worst of the financial crisis, which began in 2008. Nor can it be explained simply by cuts to family benefits. In 2015 the Socialist government did begin means-testing a payment made according to the number of children in a family. But this touched only the richest 20%.

A raft of other pro-natalist policies, from a cash bonus and tax breaks for a third child to cheaper rail travel for big families, remain in place. Maternity is considered a mark of vitality, and national pride. France still awards a “family medal”, introduced after the demographic devastation of the first world war, to parents who bring up at least four children “in dignity”. Those with more than eight used to get gold.

The best explanation seems to be that French women, like others in Europe, are delaying having children. For all births in France, the average age of the mother has increased by nearly a year in the past decade, to over 30. As women (and men) study longer, and take time to find stable jobs, the number of births to mothers aged 25-29 years has fallen from 13.4 per 100 women in 2000 to 11.2 last year. Teenage pregnancies have also dropped. So far, there has been no corresponding rise in births to the over-35s, and only a slight increase to those aged 40-49 years.

It could yet be that, in the coming years, older motherhood in France will make up for the recent fall. As Gilles Pison, a French demographer, points out, this is what happened after a previous child-bearing dip in the 1990s. Despite the sharp recent drop, the French remain among the more enthusiastic procreators in Europe. If the country can revive this breeding instinct, France will be on course, post-Brexit, to overtake Germany as the most populous country in the European Union by the mid-2050s—and for the first time since Bismarck.