Father Time is not as unforgiving as he used to be. Men and women in their 60s, so the gerontologists tell us, are younger than ever if they have lived "right." (Now they tell us.) But "right" may be in the eyes of the beholden.

"Chronologically, you might be 65, but be 55 or 60 physiologically because you have engaged in good eating habits and socialization and have a religious background that is protective," says Dr. Charles A. Cefalu, director of a new geriatric medicine program at the Medical Center of Louisiana in New Orleans.

Alas, the opposite could also be true: "You may be 65 chronologically but look 80 because you have smoked, haven't exercised enough and haven't kept blood pressure and cholesterol under control."

As Bill Cosby puts it, "I am what I ate and I'm frightened." But he looks at some of our absurd health tradeoffs. Consider the gent who steps outside at the dinner party to smoke when it's 12 degrees below zero. He might die of pneumonia, but at least he keeps others from inhaling secondhand smoke.

Knowledge is not always liberation and dreading how we decline is enough to scare most of us to death. The progress of biotechnology now holds out the promise of an ageless society, and that raises a new set of moral questions for what Leon Kass, chairman of the President's Council on Bioethics, describes as "widespread human desires to look younger, perform better, feel happier, or become more (nearly) perfect."

In a symposium at the American Enterprise Institute, he asks listeners to reflect on the good, the bad and the mischievous applications of high-tech enhancers in our pursuit of happiness.

"We want longer lives," he says. "But do we want them at the cost of living carelessly or shallowly with diminished aspiration for living well, or by becoming people so obsessed with our own longevity that we care less and less about the next generation?"

The question is not an academic one, though it lends itself to philosophical speculation over concepts of hubris, humility and human dignity. The scholarly discussions range from Genesis to "Star Trek."

Diana Schaub, a professor of political science at Loyola College in Baltimore, takes the theme of human limits from Jacques, a melancholy figure in Shakespeare's "As You Like It," who speaks of the inexorable ripening and rotting of all living things: What would happen if we could change such limitations?

Estimates of the outer limits of mortality, as currently calculated, halt at around 122 years. But science, through genetic manipulation, has already managed a sixfold increase in the life span of worms. Scientific laboratories are crawling with flies, mice and worms that are living far beyond their original life spans.

Reduced fertility and extended aging seem to be biologically linked with some lower orders of insects and animals as well as humans. Procreation also has a cultural component for homo sapiens. Continued...