Animal-grown transplant organs

When injected with rat stem cells as embryos, mice that were unable to produce their own pancreas grew a rat one instead

Numerous sources

The Scientist: 21 June 2011

The Telegraph: 21 June 2011

The original paper in Cell September 2010

The Division of Stem Cell Therapy, University of Tokyo – look for Nakauchi Stem Cell and Organ Regeneration Project