Declining global fertility and our future dependence on ART.

Since the early 1960s the world has witnessed a dramatic reduction in total fertility rates. This decline in fertility has been particularly evident in socioeconomically advanced countries including Europe, North America and the Tiger economies of East and South-East Asia. However, even in Sub-Saharan Africa, which has some of the highest fertility rates in the world, the trend has been robustly downwards over the past 25 years. Many modern economies including the USA, the UK, the European Union and Australia have used immigration as a powerful instrument to ensure consistent population growth despite sub-replacement levels of fertility. In the geographical East, immigration has not played such a key role in the management of population dynamics, with the result that countries such as Japan, China, South Korea, and Taiwan are now exhibiting negative growth. Assisted reproduction will play an important part in managing our reproductive future, although there are risks associated with becoming too dependent on this technology. If we are to manage the population's future, rather than become its hapless victims, we must develop an acute awareness of the demographic challenges facing our species and achieve a deeper understanding of the underlying mechanisms.