Ostrer has devoted his career to investigating these extended family trees, which help explain the genetic basis of common and rare disorders. Today, Jews remain identifiable in large measure by the 40 or so diseases we disproportionately carry, the inescapable consequence of inbreeding. He traces the fascinating history of numerous “Jewish diseases,” such as Tay-Sachs, Gaucher, Niemann-Pick, Mucolipidosis IV, as well as breast and ovarian cancer. Indeed, 10 years ago I was diagnosed as carrying one of the three genetic mutations for breast and ovarian cancer that mark my family and me as indelibly Jewish, prompting me to write “Abraham’s Children.”