Nature suggests there is a trade-off between reproduction and long life.
The association has already been shown in flies and now a study of the British aristocracy appears to indicate the same is true in humans. Professor Thomas Kirkwood, from the University of Manchester, and Rudi Westendorp, of Leiden University in Holland, scoured the records of 19,830 male and 13,667 female aristocrats born between the year 740 and 1875. From these records they could see that the women who had their first child at an early age died younger than those who had their firstborn later in life. Almost half the women who lived beyond the age of 81 had no children, yet fewer than a third of the women who died before that age were childless. Computerised records British aristocratic families turn out to provide an ideal database for testing the theory.