Two Regimes of 'Natural' Fertility: Non-Parity Specific Influences on High and Low Fertility Populations

Alaka Malwade Basu, Cornell University
Sajeda Amin, Population Council

In a seminal paper in 1961, Henry introduced the concept of 'natural fertility' to refer to the level of reproduction that exists in the absence of deliberate birth control. This does not mean that non-contracepting populations will all reach biologically maximum TFRs of around 16. Actual population TFRs are considerably lower because of socioeconomic and cultural factors affecting the risk of intercourse, pregnancy and a live birth. In principle, Henry's definition allows for a range of fertility outcomes in natural fertility populations, but conventional wisdom has tended to restrict the concept to the study of high fertility societies. As soon as fertility reaches near and below replacement levels, the conclusion is drawn that this is because of volitional fertility control. We question this assumption by looking at two contrasting examples of 'natural' fertility, in which little parity-specific birth control nevertheless leads to vastly different eventual fertility outcomes.