ALTHOUGH he recently lost his job, T. R. Seshadri is a contented middle-aged man. He rides a Royal Enfield motorbike and plays badminton every day. Two years ago he acquired a small flat on the outskirts of Mumbai, which he plans to rent out. Most satisfying of all, Mr Sesadri and his wife have two children, a boy and a girl—“the perfect combination”, he says.

An only child does not learn to compromise, argues Mr Seshadri. A lone boy never has to wait for his sibling to leave the bathroom and never has to concede over which television programme to watch. But three children are too many in modern India. “If someone has a third child, people will think, what the hell is he doing?” he says. Some will scornfully ask: “Did you have two daughters first?” No—two is just right.

Urban India played a starring role in “The Population Bomb”, Paul Ehrlich’s bestseller of 1968. “The streets seemed alive with people,” Mr Ehrlich wrote, of a sweltering taxi ride through Delhi that convinced him the world was heading for a Malthusian catastrophe. “People, people, people, people.” Yet India’s birth rate has contracted astonishingly quickly, and with it Indians’ notions of the ideal family. On average, city-dwelling Indians now believe that 1.9 children is perfect.

Globescan, a consultancy, has polled 19 countries on behalf of The Economist. We began by asking people to specify their ideal family size. We asked how many children they had and how many more they expected to have. We then asked people to explain why they had (or were on track to have) fewer or more children than their ideal, and how their success or failure to hit the mark had affected them. These are universal human questions. But people answer them in startlingly different ways.

More like pandas than rabbits

Our poll shows that the ideal family in Asia’s three largest countries (China, India and Indonesia) is now smaller than the ideal family in Britain or America. We also find that access to birth control is seldom much of an issue. Few young people will have more children than they want because reliable contraception was not available to them. The poll also signals a global shift. Judging by the collective desires of parents and would-be parents, more suffering is caused by having too few babies than too many.

Of the 19 countries we polled, eight are overshooting—that is, the ideal family size is smaller than the number of children people expect to have. Nigerians have gone furthest awry: on average, they think the ideal family contains 5.4 children but are on course to have 7.7. Eleven countries are undershooting. A few barely miss the target, but others fall well short. Russians regard 2.3 children as ideal; Spaniards favour 2.4; Greeks think 2.6 best. In all three, people reckon that they will end up with 1.7 children on average. Because the replacement fertility rate is about 2.1, the difference between the ideal and expected number of children in these countries is the difference between healthy natural population growth and natural decline.

Greeks are painfully aware of the gap between desire and reality. Dafni Vitali, a curator in Athens with a young son, says she feels guilty about the prospect of raising a child without a sibling but might end up doing so. Greece’s long economic crisis has shaken her confidence in the future. Perhaps life will be just as difficult in 15 or 20 years’ time, she says; perhaps it will even be worse. A man who gives his name as Nikos, who once wanted four children but has only one, says the ailing economy has greatly raised the cost of raising a large family. Although he was educated in a state school, he now regards private education as essential. The state schools have deteriorated too much.

Having the “wrong” number of children has psychological consequences, though not always bad ones. In America 39% of people who reckon they will exceed their ideal number of children report that they are more satisfied with life as a result, whereas just 8% feel sorry for themselves. Indians and Pakistanis are even more cheerful about overshooting their ideal family size, as many do. (Admittedly, Indians and Pakistanis who have fewer than the ideal number of children are also pleased, suggesting they are just rather sanguine.)

In all but one of the Western countries we polled, though, undershooting is more often felt to be bad than good. In America 15% of those who have fewer than the ideal number of children think that their life is better as a result, whereas 21% say it is worse. Having no children at all is especially painful. A 34-year-old American woman, Angela Bergmann, who has been trying to get pregnant for a decade, moved to a bad neighbourhood to scrape together the money to pay for treatment. An ectopic pregnancy left her severely depressed. “It’s hugely draining on you as a couple,” says Emily Ansell, a 30-year-old university worker in Sheffield who has twice miscarried. Many couples suffer in silence: infertility still carries a stigma.

More than anything else, people blame financial pressures and the cost of housing for having fewer children than they think desirable. Greece is not the only country where economic turmoil has put people off having children. The fertility rate in America, Australia and most of Europe has dropped since 2009. In many countries the financial crisis has been especially hard on young people, delaying the independence that many think necessary for starting a family. José Luis Marin of porCausa, a journalism and research outfit in Madrid, points out that the average Spanish man now leaves home and sets up his own household at the age of 30.

Oddly, people who live in buoyant countries like China and Mexico are even more likely to cite financial pressure as the reason for their small families. In China 80% of our respondents say that two children is ideal—an admirably cussed consensus, when one considers the fierceness with which the state enforced a one-child policy until last year. Many will not manage two, says Feng Wang, a demographer at the University of California. China’s fertility rate has fallen to 1.6, which Mr Feng ascribes mostly to urbanisation, rising university attendance and the opportunity cost of having babies in a country that is quickly becoming richer. China’s economy has been like a rocket: it can be unwise to let go even for a year.

People who have more children than they think ideal usually say that their partners wanted more, that they reckoned they could afford it or simply that they love babies. Only 13% explain that they did not use birth control or that it was unavailable. And this seems to be a shrinking problem. Whereas 21% of people aged 55 or over blame their larger-than-ideal families on a lack of reliable contraception, only 6% of people under 35 do so.

In India roughly half of married women use birth control, and in much of Africa the rate is far lower. But many people who do not use contraceptives see no need for them. In some countries, such as Nepal and the Philippines, many husbands and wives live apart because one partner is working abroad. In others women of childbearing age are often trying to get pregnant, are actually pregnant or recently gave birth. The Guttmacher Institute in New York estimates that, although 85% of married women in Nigeria are not using birth control, the proportion who have an “unmet need” for it is just 16%.

“In our place they believe in many children,” explains Esther Okafur, a mother of nine who lives in Ajah, a slummy suburb of Lagos. In Nigeria’s rural districts, where children start working young, a large family means a more productive farm—“like you have a tractor on it”, says a driver from Mrs Okafur’s neighbourhood. As well as having a culture of large families, Nigeria is patriarchal and pious. Men say that babies are God’s will; women report that they have little say in the matter, at any rate.

But Nigerians are no more immune to the family-shrinking pressures of urbanisation and economic change than Europeans or Asians have been. Mrs Okafur followed her husband to Lagos two months ago to look for work. In the city her large brood is a burden. She says she would like to send her children to school but cannot afford it. Other urbanites increasingly desire smaller families, which helps explain why the ideal family size in Nigeria is two children smaller than people’s expectations. Especially in the mostly Christian south, wealthy Nigerians are marrying later, says Olayinka Akanle, a sociologist at the University of Ibadan. Bank advertisements targeting monied folk paint a picture of two-child domestic bliss.

Reliable contraception is important, and will become even more so in countries like Nigeria where couples increasingly seek smaller families. But the assumption that family planning should be all about birth control is a 1960s relic. In a growing number of countries, the problem of getting hold of contraception is giving way to the problem of getting pregnant. As Mr Feng puts it, unmet need is being replaced by unmet demand.

As our poll shows, people in wealthy countries consistently want bigger families than they get. Couples start having children late and find it increasingly difficult. A 30-year-old woman has a roughly 20% chance of getting pregnant each month, falling to about 5% by the age of 40. The resulting baby shortfall is painful for couples and alarming for governments, which worry about the long-term solvency of old-age-pension systems.

In poorer countries infertility is more often caused by infections—some of them sexually transmitted, others picked up following childbirth. It is often a social emergency, especially for wives—“You can be sent out of the house and buried in a different graveyard,” says Joe Leigh Simpson, head of the International Federation of Fertility Societies (IFFS). Gradually, though, poor-world infertility is changing from a kind of random crisis visited upon some people to a broad difficulty affecting many.

That change can be seen in the Mumbai suburb of Thane, in the Cocoon fertility clinic run by Anagha Karkhanis. Some of the patients Dr Karkhanis sees would be unfamiliar to European or American fertility specialists. Couples who have been married little more than a year visit to ask about IVF (almost invariably, they assume the problem lies with the wife rather than the husband) with a mother-in-law or another close relative in tow. Some of the women are as young as 24. Couples frequently ask whether she can help them to have a boy. Sex selection is illegal in India but common, and is usually done by aborting female fetuses.

But Dr Karkhanis also sees the kind of people who fill waiting rooms in Western fertility clinics—couples who got going on family life rather late, having devoted years to their careers, and are now finding it hard to conceive. Some are handicapped by diseases of affluence: they drink too much alcohol, smoke, or are obese. She tries to dissuade women over the age of 50 from IVF treatment, although other clinics do not. The IFFS estimates that India now has 1,000 fertility clinics—more than any other country. Good clinics are appearing in African cities too, according to Mr Simpson.

The people who fretted about an exploding population half a century ago made two mistakes. They failed to imagine that agriculture could become far more productive. They also failed to predict that birth rates would fall so sharply. That is to their discredit, but it is understandable. Almost nobody could have believed that a country like India would end up suffering a shortage of children.