As the world's population reaches 8 billion inhabitants, China, the planet's most populous country, is suffering from a demographic crisis. In ten years, the number of births has halved. After four decades of the One Child Policy, the Chinese government now allows families to have two, sometimes even three children. But the policy reversal isn't enough to convince would-be parents. Education in China is one of the most expensive in the world and younger generations are turning down traditional family models. More and more women are prioritising their careers, despite social pressure. Our correspondents report.