As Dr. L. Scott Levin holds his hand, double-hand transplant recipient eight-year-old Zion Harvey moves his fingers during a news conference Tuesday, July 28, 2015 (AP Photo/ Matt Rourke)
Double-hand transplant recipient eight-year-old Zion Harvey arrives to a news conference with his mother Pattie Ray Tuesday, July 28, 2015 (AP Photo/ Matt Rourke)
As Dr. L. Scott Levin holds his hand, double-hand transplant recipient eight-year-old Zion Harvey moves his fingers during a news conference Tuesday, July 28, 2015 (AP Photo/ Matt Rourke)
Double-hand transplant recipient eight-year-old Zion Harvey smiles during a news conference Tuesday, July 28, 2015, at The Children’s Hospital of Philadelphia (AP Photo/ Matt Rourke)
Double-hand transplant recipient eight-year-old Zion Harvey smiles during a news conference Tuesday, July 28, 2015, at The Children’s Hospital of Philadelphia (AP Photo/ Matt Rourke)
Pattie Ray speaks with her son double-hand transplant recipient eight-year-old Zion Harvey during a news conference Tuesday, July 28, 2015 (AP Photo/ Matt Rourke)
Double-hand transplant recipient eight-year-old Zion Harvey accompanied by Dr. L. Scott Levin, left, and his mother Pattie Ray, stands during a news conference (AP Photo/ Matt Rourke)
As Dr. L. Scott Levin holds speaks with double-hand transplant recipient eight-year-old Zion Harvey during a news conference Tuesday, July 28, 2015 (AP Photo/ Matt Rourke)