PM Lawrence Wong recently addressed Singapore's declining fertility rate, acknowledging that birthrates are falling across the developed world and that no single cause has been identified. There were, he noted, many hypotheses.
I think the difficulty in naming a cause isn't because the cause is genuinely unknown. It's because the cause is structural, and pointing to a structure implicates the entire system that built it.
The biology is simple
In a controlled environment, any animal will breed prolifically when three conditions are met: space, abundance of resources, and the absence of felt threat. Remove any one of those conditions and reproduction slows. This isn't theory — it's observable in any lab, any wildlife population, any ecosystem under pressure.
Human beings are not exempt from this biology. We've just built an enormous cultural superstructure on top of it that makes us forget it's there.
Apply those three conditions to daily life in a dense, high-cost, high-performance city and the picture becomes clear. Space is scarce and expensive. Resources — time, money, housing, childcare — feel perpetually insufficient. And the ambient pressure of a society organised around achievement and output produces a low-grade felt threat that never fully resolves.
It isn't that people don't want children. It's that the conditions don't signal safety. And at some level below conscious reasoning, the body knows this.
Why no single policy fixes it
Government programmes address the symptoms: baby bonuses, extended maternity leave, subsidised childcare. These are not useless. But they operate at the surface of a much deeper structural condition.
You cannot solve a problem of felt scarcity and felt threat with a cash transfer alone. The body's assessment of safety is holistic. It reads housing costs, work culture, social expectations, physical space, and the general texture of daily life — all simultaneously. A baby bonus doesn't change that texture.
No matter all the hundreds of programs you can think about, it all boils down to two things: a sense of freedom, and abundance.
Countries where birthrates are declining more slowly tend to share certain qualities: more physical space per household, stronger social safety nets that reduce the felt stakes of financial uncertainty, and work cultures that don't treat parental leave as a career risk. These aren't policies. They're environmental conditions.
The design question
If birthrates are a design problem, the question becomes: what would a city designed for human reproduction actually look like? Not for efficiency, not for GDP per capita, but for the conditions under which people feel safe enough, resourced enough, and free enough to bring another life into the world?
That's a different brief from the one most cities are built to. And it's worth asking whether any city has seriously tried to answer it.
I don't have the answer. But I think naming the right question is a reasonable starting point — and "we don't know why birthrates are falling" is not the right question.