Natural fertility and longevity.

Much empirical work suggests an association between fertility patterns and longevity. I review this association, focusing on natural fertility populations and emphasizing the role of both the timing and the intensity of fertility. Overall, it appears that although age at last reproduction routinely correlates with post-reproductive longevity, suggesting a slower rate of senescence among late fertile women, the same is not true for age at first reproduction and parity. I discuss some of the conceptual and methodologic issues, as well as the sources of the biases, that have been a persistent feature of this body of research. I conclude by suggesting avenues of research that could be initiated or pursued in the area.