BORDEAUX: The stakes have just been raised. No longer is it enough to stretch your life expectancy to some vague horizon. Now you are expected to strive for 100, and adjust your life to get there.

I was at a dinner party recently where four of the guests had just taken a longevity test on the Internet and were arguing over their scores. One chic 50ish Frenchwoman claimed victory with her estimated checkout age as 102. The reset of us sheepishly acknowledged defeat.

These tests are tapping in to a new competitive urge to reach 100 and still have your marbles. How-to books, Web sites and geriatric clinics are proliferating as life expectancy grows.

The number of American 100-year-olds has been doubling about every 10 years since the 1950s, according to researchers at the New England Centenarian Study at Boston University. There are 80,000 American centenarians alive today, and the U.S. Census Bureau predicts near 500,000 by the year 2040.

In Britain, Queen Elizabeth sends letters to each new British centenarian. She totaled 255 letters when she became queen in 1952; last year her staff wrote 4,623 for her to sign.

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