Beginning in 1960, a phenomenon occurred that John Caldwell named the ‘global fertility transition’ (Caldwell, 1997), in which fertility declines have become the general rule throughout the world, including in the majority of the less developed countries. This is important partly because fertility is in many circumstances negatively associated with socio-economic development (Bryant, 2007). From 1970–75 to 2005–10, the average total fertility rate (TFR) for the developing world fell by half, from 5.4 to 2.7 births per woman on average (United Nations, 2011). However, global figures hide important differences in fertility levels among the different regions. In Asia and Latin America, the reproductive behaviour of women reflected the pattern of change noted by Caldwell, halving the TFR in the last 35 years. In Africa, on the contrary, fertility stagnated at 6.2–6.4 from 1950 to 1985, and then began a decline that was much slower than in other developing regions. As a whole, the TFR of sub-Saharan Africa has, for decades, been higher than the fertility levels elsewhere. This was the case in 1950 and 1975, and remains so today. Fertility differences among countries are now larger than ever because transitions to replacement fertility have not yet started in some subpopulations of Western and Middle Africa, but have already been completed in others (e.g. in the economically most advanced countries of Asia, especially East Asia, as well as in many countries in Latin America and the Caribbean). As a result, the observed TFRs of (former) developing countries in 2005–10 range from a high of 7.1 in Niger to a low of 1.0 in Hong Kong. All regions of the world experience wide variations in their TFRs. For instance, East Asia has experienced a faster fertility decline than countries like Pakistan in south-central Asia. Moreover, fertility levels can show significant variations within a single country. This is the case in India, where Northern and Southern patterns of fertility are very different. Overall, regional variations are most apparent in sub-Saharan Africa.