The two infants, 11 months and eight months old, suffered from a rare life-threatening disorder called severe combined immunodeficiency. Because a genetic mutation kept their immune systems from fending off even the most innocuous infections, both faced lifelong confinement in sterile shielded environments. Now, 10 months after undergoing treatment in France to correct the defect, these "bubble babies" are out of their bubbles--back at home and acting for all the world like normal babies.
Doctors have successfully treated many young SCID patients before with various types of bone-marrow transplants. What distinguishes these two babies, researchers reported in Science last week, is...