"He thinks very, very out of the box, and I think that's one of the penalties you get for thinking out loud about things and wondering about them," Stillman said. "He challenges people to think about issues, and you get into trouble doing that."
Watson also was the first director of the Human Genome Project, an international project aiming to sequence the human genome, but resigned in 1992. The project ended in 2003, establishing the order of the 3 billion letters in the genome, which can be thought of as "the book of life."
Between insights from the genome project and the double helix structure, DNA has proved to be important in surprising areas, Watson said, from DNA fingerprinting to diagnosing risk for genetic disease. DNA will probably be essential in future cures for cancer, because cancer arises from changes in DNA, Watson said.
"I don't want to die until I see cancer cured," he said with a laugh. "Because I think it could happen."
On the sunny grounds of Cold Spring Harbor, Watson dons a white floppy hat and glasses. These days, he's interested in how exercise prevents disease such as cancer, and says he has some unpopular ideas about antioxidants and diet.
Among Watson's current activities is writing a book about his father and his family called "Father to Son." He's learned that he descended from a Watson living in Springfield, Illinois, who decided to go on the Gold Rush.
When this ancestral Watson returned, he established a confectionery store where -- according to James Watson -- Abraham Lincoln used to buy desserts. The ancestor also founded a large resort hotel in the Midwest, which wouldn't have happened unless he'd taken a big chance to go look for gold.
As far as Watson, "DNA was my only gold rush," he said. "I regarded DNA as worth a gold rush."
Besides genetics and curing cancer, Watson has been thinking about his age. He used to not want to get to 90 because it's "hard to find role models" among that age group, and now he finds it hard to find desirable conversation partners among his peers.
"The brain doesn't have to..." Here he pauses and looks up at the ceiling.
"... sort of, be unimaginative when you're older, but you almost have to move in a world where people are young, to make you think that way."