- Scientists in England have crossed a major hurdle to creating blood cells in the lab
- Using stem cells, the researchers made 'immortal' cells that create an unlimited supply of red cells
- It will be years before these cells are put to use in the hospital, and only for a small subset of patients
- Volunteer blood donors will still be needed
(CNN)For decades, scientists have sought to create red blood cells in the lab -- a "holy grail" that some hoped could ease regional blood shortages, especially for people with rare blood types.