The authors of this Views and Reviews outline the current understanding of the association between fertility and longevity. Natural fertility in populations that did not employ any contraception make up the model that attempts to define this relationship. Longevity seems to be increased in women with late-age conceptions and may be the result of genetic or environmental factors or both. A new concept is suggested that demonstrates the potential rejuvenating effect of pregnancy on older pregnant mothers. The link between infertility itself and conceptions at an older age with morbidity and mortality is summarized.