Setting the Stage: A Generation of Centenarians?

Most people alive today in Germany, Italy, Japan, and the United States will probably live through most of the twenty-first century. Half of the girls born today in Minneapolis, Tokyo, Bologna, and Berlin will probably celebrate the dawn of the twenty-second century as centenarians. Boys are disadvantaged, but half of the males born today in the postindustrial world will probably survive to age 95.

These are the most important but least discussed facts about the demography of longevity. Very long lives are not the distant privilege of future generations. Very long lives are the probable destiny of most people alive today. For everyone in his or her thirties and younger, especially children, life-spans of 95 or 100 years will be common.

Suppose when you are young you know you will probably live to be 100. How will you want to spend your life? You probably want a broad education--science and literature, history, music, and art--because you want to stay productive and amused for a long time. You probably do not want your life divided into three blocks--spending your first 25 years studying hard to be educated, the next 35 years working hard to earn a living, and the final 40 years in enforced leisure.

Instead, you probably want to mix education, work, and leisure over the course of your life. Then, you have time for your children when they are young and need you and want to see you. A few years later you will have time to reorient your knowledge and start a different career. You probably value this mix of education, work, and leisure even if--indeed, especially because--it means that you leave the house and go to work, at least part time, when you are in your seventies and eighties. Many people in the United States and Japan already work past age 60 or 70.

People will want to work longer for two reasons. First, most of our children will be much healthier when they reach age 70 or 80 than we are today. Indeed, every successive generation is becoming healthier at older ages. They will live to age 95 or 100 because they will be so healthy and active at age 80. Second, people will want to work later in life so that they do not have to work so hard earlier in life. We all must contribute something to get the world's work done, but we do not have to jam our contribution into that period of life when our children need us.

Most of the people alive today in Japan, as well as in China, in the United States as well as in Mexico, in Italy as well as in Turkey, will probably still be alive half a century from now, in 2050. Public policies to address the new demography of longevity should be far sighted and long term--policies that will work not just today but decades from today. In particular, they should be designed to respond to the new needs of people who will probably live a very long time.

I say "probably" because there is a lot of uncertainty about death. On the one hand, biochemical warfare, epidemics worse than AIDS, nuclear terrorism, and environmental collapse could make life nasty, brutal, and short. On the other hand, the biological and biomedical sciences appear to be poised today just as the physical and engineering sciences were a century ago. The twentieth century brought us cars, airplanes and rockets, telephones, television, computers, and the Internet. The twenty-first century may well bring us cures for cancer, stroke, and Alzheimer's, genetic engineering, and perhaps even deep understanding of the aging process. Then our babies may live not 100 years, but 120 years, 150 years, or perhaps indefinitely. Perhaps every decade that you live will produce a decade of new biology, letting you live another decade. This is possible--improbable, but possible.

If so, the...