These nematode worms are smaller than a grain of sand.

In "Genes for Youth" Alan visits with scientist and nematode worm expert Dr. Cynthia Kenyon at the University of San Francisco. Kenyon is particularly interested in the aging process, and her worms have provided some amazing insights. "How could the way a worm ages be anything like the way we age?" asks Alan.

As Alan soon learns, old age effects nematode worms and humans in much the same way. Younger organisms tend to writhe happily about while their elder counterparts, all of twelve days old, prefer to take it easy, their aging muscles showing visible signs of deterioration.

Kenyon uses a giant worm model to demonstrate how to halt the aging process.

In an attempt to uncover a gene that controls aging, Kenyon used chemicals to create various mutations in healthy worms. She then followed the worms closely over several generations. In most cases, the mutated genes decreased overall life span. But in some remarkable cases altering a single gene allowed a worm to live more than twice as long as normal. Kenyon's discovery has brought to light much about the way our own life span system works. As Alan says, maybe his wish to live to 106 isn't so crazy after all.