Y: A mistake? Why?

D: Because science is giving us longer lifespans all the time. Researchers these days are even starting to understand how the body sends signals to itself, determining how it ages.

Y: Now that sounds like science fiction.

D: It's true. A recent study conducted by James Carey and his colleagues at the University of California, for example, found a link between how long a mouse lives and its ovaries.

Y: Its ovaries? What do they have to do with aging?

D: The researchers removed the ovaries of one set of mice when they were a few weeks old. Those mice didn't live as long as mice who still had their ovaries. Another group of mice had their ovaries removed but got young ones later. The mice with the young ovaries implanted into them lived forty percent longer than the ones who kept their original ovaries, and sixty percent longer than the ones with no ovaries at all!

Y: Yowza--sixty percent longer!

D: Some chemical message is being sent from the ovaries to the rest of the body, telling it what stage of life it is in. By renewing their ovaries, the scientists were essentially able to set the clock back.

Y: So who wants mice to live longer?

D: Mice are just a test. If we could understand how the body tells itself to age, maybe we could make other species live longer...like people.