MANY women in the richer parts of Asia have gone on "marriage strike", preferring the single life to the marital yoke. This helps to explain why their fertility rates have fallen. But Asia is not alone. According to the United Nations, in 83 countries and territories around the world, women will not have enough daughters to replace themselves unless their fertility rates rise. In Hong Kong, for example, a cohort of 1,000 women is now expected to give birth to just 547 daughters. If nothing changed, those 547 daughters would be succeeded by 299 daughters of their own, and so on. Extrapolating wildly, it would take only 25 generations for Hong Kong’s female population to shrink from 3.75m to just one. Given that Hong Kong’s average age of childbearing is 31.4 years, the territory would expect to see the birth of its last woman in the year 2798. By the same unflinching logic, Germany, Italy, Japan, Russia and Spain will not see out the next millennium. Even China has only 1,500 years left.