Cellular Biology: Stem Winder

When James Thomson learned last week that President Bush was about to make his big decision on stem cells, he coolly decided to do what he had planned to do all along. The once obscure University of Wisconsin scientist had triggered the great debate over embryonic stem cells. And so, on the morning after listening to the President's speech at a neighbor's house ("I don't have television," Thomson says. "I just watch DVDs on my computer"), he blithely went off hang-gliding in the hills near Madison. Good thing. As the lab Merlin who was first to create the magical cells in a Petri dish, Thomson knew his telephone would be jangling after the President's pronouncement. "I thought it better to clear my head before facing the media storm," he says, leaving calls unanswered.

Though somewhat disappointed with the restriction on creating new cell lines--he's cultivating five right now--he's generally pleased with the Bush decision. "The field will now go forward. It won't be limited to just a few labs, even if there are only a few dozen cell lines," he says. "That's the most important thing." Such altruistic concern for the progress of his chosen science is characteristic of the man. Even before he was caught in the limelight, he went about his experiments so conscientiously that they set the ethical standard by which all research in the field is measured.

In November 1998, when he was just nudging 40, he not only succeeded in culling stem cells from "surplus" embryos created at fertility clinics but also kept them alive and reproducing indefinitely. In effect, he stopped their biological clocks by preventing the cells from morphing into different tissues, as they would in undisturbed embryos. In the jargon of cell research, they were immortal. Only a few days later, fellow stem-cell researcher John Gearhart of Johns Hopkins University published word that he had succeeding in cultivating a line of stem cells from the germ cells of aborted fetuses--though he graciously conceded that Thomson was ahead in the overall race.

These were astonishing achievements. For the first time, scientists had access to a cornucopia of undifferentiated cells that can grow into any one of the 200 or so cell types that make up a human being. That opened the door to remarkable possibilities, including replacement cells for malfunctioning pancreases, injured spinal cords and plaque-clogged brains. It also brought stern warnings. Though the sacrificed embryos were no more than hollow, pinhead-size clusters of a few dozen cells, destroying them for whatever purpose represented, in the mind of many antiabortion conservatives, an assault on a human life.

Thomson, a tall and rumpled Ichabod Crane, is ill cast as a lightning rod. A developmental biologist at the University of Wisconsin's primatology center, he traces his passion for science to an inspirational rocket-scientist uncle. Imagine, the uncle once told him about his work for NASA, "they pay me to do this."