Kass, he said, is among those who ask the "ultimate" questions. "Kass is a terrific teacher," Callahan added. "He wants to hear both sides of the argument. Though on issues like cloning, Kass has a position. He can work with Washington."

Kass is highly regarded by other bioethicists, even those who are his critics. Ronald M. Green, director of the Ethics Institute at Dartmouth College, speaks for many when he says of Kass: "I disagree with many of his conclusions. But I think Leon Kass has been extremely intelligent and thoughtful. He plays an important Cassandra role. We've seen terrible abuses in the quest for biological perfection (for instance, eugenics) and the over-medicalization of our world. Kass helps us to move forward with our eyes wide open."