The Way We Age Now: Reporting & Essays: The New Yorker

Today, the average life span in developed countries is almost eighty years. If human life spans depend on our genetics, then medicine has got the upper hand. We are, in a way, freaks living well beyond our appointed time. So when we study aging what we are trying to understand is not so much a natural process as an unnatural one. Inheritance has surprisingly little influence on longevity. James Vaupel, of the Max Planck Institute for Demographic Research, in Rostock, Germany, notes that only six per cent of how long you’ll live, compared with the average, is explained by your parents’ longevity; by contrast, up to ninety per cent of how tall you are, compared with the average, is explained by your parents’ height. Even genetically identical twins vary widely in life span: the typical gap is more than fifteen years.