The BBC reported that this was the strongest warning yet from the UN agency on falling birth rates.

Namrata Nangia, who lives in Mumbai with her husband and five-year-old daughter, said they’ve been thinking about having another child. But every time, they come back to the same question: “Can we afford it?”

Namrata works in the pharmaceutical industry. Her husband works for a tyre company. She says even raising one child is expensive  from school fees to swimming classes to doctor visits. “When I was young, we just went to school. But now you have to send your kid for extra things  swimming, drawing, other activities,” she said.

On top of costs, time is another problem. She commutes around three hours a day and says she barely has the energy after work. “After a working day, you have that guilt as a mother  that you’re not spending enough time with your kid,” she said. “So, we’re just going to focus on one.”

The survey included a mix of countries  from low to high-income  such as India, South Korea, Brazil, the US, Italy, and Nigeria. Together, these countries represent a third of the world’s population.

The UNFPA said 39% of people cited financial pressure as the main reason for not having more children. The highest percentage was in South Korea (58%), and the lowest was in Sweden (19%).

Time was another major barrier. Many people said work and long commutes leave little energy for family life. Infertility was a smaller factor, mentioned by 12% overall. However, in countries like Thailand, the US, South Africa, Nigeria, and India, the number was higher.

In India, 13% of respondents pointed to infertility as a reason for having fewer children than they wanted.

Until now, the UN agency mostly focused on reducing unwanted pregnancies and improving access to contraception. But this report marks a shift in approach. “This is the first time the UN has really focused on low fertility,” said Professor Stuart Gietel-Basten, a demographer at Hong Kong University of Science and Technology.

He said some countries have gone from worrying about too many people to encouraging childbirth. “Forty years ago, countries like China, Korea, Japan, and Thailand were concerned about high population. By 2015, they were trying to increase birth rates,” he said.

Dr Kanem warned against extreme policies that try to control how many children people have. “There’s a lot of talk about population crisis, whether it’s too many or too few,” she said. “This can lead to panicked or manipulative policies.”

Professor Gietel-Basten added, “Low fertility, population ageing, and slowing growth are being used as excuses for nationalist or anti-migrant policies.” UNFPA will expand the research later this year to include 50 countries.-Agencies