For the first time doctors have successfully transplanted a vein grown with a patient's own stem cells, another example of scientists producing human body parts in the lab. In this case, the patient was a 10-year-old girl in Sweden who was suffering from a severe vein blockage to her liver. Last March, the girl's doctors decided to make her a new blood vessel to bypass the blocked vein instead of using one of her own or considering a liver transplant.