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While none of these therapies would take human beings anywhere near the tripled and quadrupled life-spans achieved in fruit flies and nematodes, they could at least improve our life expectancies--the number of years even our shortened telomeres and caramel-gummed cells would allow us to achieve if illness didn't claim us first. For much of the time our species has been on the planet, that figure is thought to have been a mere 20 years--barely long enough for contemporary people living contemporary lives to move out of their parents' home. The fact that those lives now routinely exceed 80 years is a monumental achievement. A little more progress in studying telomerase, glycosylation and other aspects of senescence science, and researchers like Butler believe there's no reason today's adults could not realistically hope to see 120.
For people dreaming of immortality, that prospect may fall a little short. But for those of us who are contemplating a life that ends around age 80, four or five additional decades sounds like a splendid first step.
--With reporting by Elaine Lafferty/Los Angeles, Alice Park/New York and Dick Thompson/Washington