Like some 150 other young children in the U.S., 21-month-old Alyssa Smith was waiting for a new liver, her one chance to avoid death at an early age. Her prospects did not look bright, since the supply of livers taken from cadavers and suitable for transplant is critically slim. But last week a team of surgeons at the University of Chicago Medical Center gave the little girl from Schertz, Texas, her chance to live. And what seemed truly miraculous about the operation was the source of Alyssa's new liver: her mother.
In a 14-hour procedure, the surgeons removed the fist-size left...