"¿Aging societies' with increasing life expectancies of the average of all their members are facts in modern history that are disputed by nobody. What is disputed by the most renowned names in demography, however, is that aging populations are a consequence of the fall in mortality and thus the increase in life expectancy. It is claimed that the [principal] reason for ¿aging' is to be found in a drop in fertility. In this sense today's demographers regard as a standard result: ¿Variations in fertility are of more significance for the age structure of populations than variations in mortality'. In the following paper this thesis, which is based on a neo-Malthusian interpretation of the role of fertility in the demographic process, will be questioned."