Moritz and Esther Abram Flexner were Jewish immigrants to Louisville. They were married in 1856 in Jefferson County, KY. He was a successful merchant. They had nine children: Abraham Flexner, Bernard Flexner, Jacob Aaron Flexner, Gertrude Flexner Baldauf, Simon Flexner, Isidor Flexner, Henry M. Flexner, Mary Flexner, and Washington Flexner. Two of their sons, Jacob and Simon, were respected physicians in Louisville, and Abraham, an educator, was instrumental in changing the face of American medical education and research.