Jewish areas in London have the highest concentration of stem cells donors, according to the Anthony Nolan charity.
The charity has mapped its register of bone marrow donors for the first time, and shows Finchley and Golders Green as the area with the most donors, with Hendon second.
Anthony Nolan attributed the result to campaigns such as Spit4Mum, set up by a Jewish family whose mother Sharon Berger, needed a bone marrow transplant.
Communications Manager Emily Rosselli said: "Without campaigns run by Jewish families these areas would not be top."
