THE 1980s, Ralph Snodgrass' interest in developmental immunology led him to Switzerland, where his research allowed him to work with a profound biological discovery: embryonic stem cells-often called miracle cells or miniature fountains of youth-which, as Snodgrass would later write in scientific journals, had the ability to produce every type of cell in the body, opening the way for experiments on blood and genetic diseases.

Because this was the 1980s, science was still in the stem cell dark ages. The human embryonic stem cell was isolated only six years ago by University of Wisconsin biologist James Thomson. Snodgrass was limited to working on mouse embryonic cells.

Snodgrass is not someone you would automatically associate with lab coats and microscopes. He is athletic, a mountain climber, prideful enough that he doesn't like his age printed in the newspaper. When I ask him about Thomson's breakthrough, which has led to the most contentious politico-science conflict in 30 years, Snodgrass turns competitive. "From the mouse stem cells, we knew all this stuff long before Jimmy Thomson ID'd the human embryonic stem cell," he...