Stem cell research—and investment into it—has been largely inspired by the hope of using stem cells to regenerate, repair or replace damaged tissue or even whole organs. Stem cell‐based therapies promise to eventually solve the problems associated with conventional organ transplantation: notably tissue rejection, a shortage of donors and the poor quality of donor organs. A much improved knowledge of the factors needed to coax stem cells to differentiate into specialized cells, in combination with advances in tissue engineering, has brought that promise closer to reality. Specific tissues and even whole organs generated from stem cells can now be grown in vitro and then transplanted into a patient to continue their development in vivo . Scientists have already successfully transplanted relatively simple laboratory‐grown organs, such as the bladder and wind‐pipe, and have for decades conducted now‐standard skin and bone marrow transplantation. > Specific tissues and even whole organs generated from stem cells can now be grown in vitro and then transplanted into a patient to continue their development in vivo The first laboratory‐grown internal organs were transplanted in 1999 in the USA, although the results were not reported until 2006, after tracking the patients for several years [1]. These first transplants did not involve the specific differentiation of stem cells, but they established that laboratory‐grown organs could be transplanted and subsequently function correctly. The team involved, under the leadership of Anthony Atala, Director of the Wake Forest Institute for Regenerative Medicine in Winston‐Salem, North Carolina, implanted laboratory‐grown bladders into seven children with spina bifida and severely malfunctioning bladders. They extracted cells from the children's malfunctioning bladders and used them to grow thin sacs of tissue in the laboratory. These rudimentary organs were then grafted back on to the patients' own bladders. The work was an important stepping stone and …