A new frontier in medical science is making a historic splash in the way many researchers are thinking about the aging process. The length of our telomeres (protective caps at the ends of chromosomes that fray away and diminish naturally as we get older) may hold the key to discovering how well our bodies will age and our susceptibility to chronic illnesses. Molecular biologist Elizabeth Blackburn–listed as one of Time magazine’s 100 “Most Influential People in the World” in 2007, won the 2009 Nobel Prize in physiology or medicine (along with collaborators Carol Greider and Jack Szostak of Harvard Medical School in Boston) for her groundbreaking work in telomeric DNA, helping put telomeres science at the center of mainstream health consciousness. Far from being a bio-marker tell-all revealing the exact length of a genetically fated lifespan, telomeres research, dubbed by many as the science of longevity, is more akin to “an integrative indication of health,” as Blackburn, now a molecular biologist at the University of California, San Francisco (UCSF), put it. By gauging your susceptibility to age-associated illnesses like heart disease and cancer, researchers and physicians may be able to help patients tailor lifestyles that stymie their vulnerability to chronic diseases in the future.