A 10-year old UK boy is the first child to receive a windpipe transplant with an organ made from his own stem cells, the BBC reports. Using his own tissue should reduce the risk of rejection, doctors hope, who say he is doing well and breathing normally. This is the first time a child has received a stem cell organ transplant, and the longest airway to be replaced (the first-ever tissue-engineered windpipe transplant was done in Spain in 2008, but with a shorter graft). The boy has a rare condition called Long Segment Congenital Tracheal Stenosis, where parents are born with a narrow airway; when he was born, his airway was just one millimetre across. To build a new airway, doctors took a donor trachea, stripped it to collagen scaffolding and injected it with stem cells from bone marrow.