The candles on your birthday cake don't tell the whole story. As anyone who ever attended a high school reunion can tell you, ...

A new kind of blood test could be used to predict future disease risk. Here is what it means for the detection of diseases ...

Add Yahoo as a preferred source to see more of our stories on Google. Biological age tests are becoming popular with biohackers and longevity seekers. They're not perfect health indicators, but they ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." How old are you, exactly? That used to be an easy—if impertinent—­question to answer. It turns out the ...

How old are you, exactly? That used to be an easy—if impertinent—­question to answer. It turns out the truth is a moving target. There’s your chronological age—the number of candles on your birthday ...