There are some countries in the world where a high birth rate is a major worry, especially when the country is less economically developed, and resources to feed and care for children are scarce. But in other countries, the opposite is the case. The birth rate in several rich countries is falling, at the same time as older people there are living longer. This will become a problem as time goes on, because there will be far more old people who need looking after, but far fewer younger people to do that. By allowing birth rates to fall so much, these countries are storing up a problem for the future.