In this photo taken, April 12, 2011, Dr. Reggie Duerst, left, a stem cell specialist, and nurse Becki Maloney, center, greet stem cell donor Marshal Davis at Children's Memorial Hospital in Chicago. ... more 
In this photo taken, April 12, 2011, Dr. Reggie Duerst, left, a stem cell specialist, and nurse Becki Maloney, center, greet stem cell donor Marshal Davis at Children's Memorial Hospital in Chicago. Davis was visiting the hospital with the Kowaliks to meet the staff that performed the transplant. The 31-year-old donor added his name to a bone marrow registry over a decade ago when he was a student at the University of Florida. He got the call to be a donor in 2009 when he was told he was nearly a perfect match with Kowalik. Doctors said abnormalities in Jacob's marrow would eventually develop into acute leukemia without the transplant. less 
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Associated Press | Photo By M. Spencer Green
Sun, May 1, 2011 2:45 PM EDT