This project tackles the question of how, on the one hand, the high life expectancy and, on the other, the increasing age of mothers at childbirth will impact the joint lifetime of three and four generations and will develop in future. To this end, indicators are derived from the official data on mortality and fertility for the mean joint lifetimes of three- and four-generation families. Because of the data available, the investigation will be restricted to the female succession of generations, and here to an observation of the first-born child in each case. The indicators act as model calculations, which is why they serve above all to indicate (future) developments in mean joint lifetimes. The indicators are calculated for the average jointly-spent lifetime of three-generation families for the period from 1990 to 2060, and of four-generation families for the period from 2010 to 2060.