His parents weren't married, and due to the chaos in Europe caused by World War II, the story of his early life is remarkable, but the details are unclear.

[14] Prior to her arrest[15] she had made contingency plans by selling her belongings and giving the proceeds to a nearby peasant family to care for her child.

His mother survived the war in Germany (part of the reason the details of his early life are unclear is that she would never talk about her experiences), and when it ended she began a year-long search for him.

She finally found him on his ninth birthday in a hospital bed in Reggio Emilia ill with a fever and subsisting on a daily bowl of chicory coffee and bread crust.

She took him to Rome, where he had his first bath since he had left her care and where, with money sent by his uncle, Edward Ramberg, an American physicist at RCA, they made arrangements to depart to the United States.

He and his mother moved to Pennsylvania to live at an "intentionally cooperative community" called Bryn Gweled,[19] which had been co-founded by his uncle.

[28] For this work, Capecchi was awarded the 2007 Nobel prize for medicine or physiology, along with Martin Evans and Oliver Smithies, who also contributed.