James Till and Ernest McCulloch prove that there are stem cells, by identifying self-renewing cells in mice bone marrow (T2).

James Thomson and John Gearhart are the first people to isolate embryonic stem cells, and grow them in a laboratory (T2). 

Anthony Atala grows seven bladders in a laboratory with cells taken from the patients. He successfully transplants all 7 bladders into his teenager patients (T2). 

Shinya Yamanaka finds a way to make adult cells act like embryonic stem cells by reprogramming it's genetic material; known as induced pluripotent stem cells (T3).

Cells are taken from patients who've had heart attacks. Cells are grown in a lab and then re-injected into patients to regrow dead heart tissue (T4). 

Human skin cells are transformed into ES cells by removing the DNA from an egg cell and replacing it with the skin cell material. These cells can be reprogrammed to act like ES cells through the process of somatic cell nuclear transfusion (T1, T4). 

During clinical trials, 18 blind patients were injected with ES cells. Half of the patients were reported to have improved eyesight (T2). 

Katsuhiko Hayash took mouse skin cells and cultured them in egg cells. These cells became pups once fertilized (T2).