Two stem-cell researchers have won this year's Nobel Prize in Physiology or Medicine for their groundbreaking work in cellular reprogramming, a technique that unleashed a wave of advances in biology, from cloning to the possible treatment of diseases using a patient's own cells.

Experiments by John B. Gurdon of the United Kingdom and Shinya Yamanaka of Japan showed that mature cells taken from the body could be changed to an embryonic-like state in a laboratory dish, a head-spinning discovery that is the biological equivalent...