Born Betty Jean Jennings in Gentry County, Missouri, in 1924, she was the sixth of seven children. Her father, William Smith Jennings (1893-1971) was from Alanthus Grove, where he was a schoolteacher as well as a farmer. Her mother, Lula May Spainhower (1887-1988) was from Alanthus. Jennings had three older brothers, William (January 10, 1915) Robert (March 15, 1918); and Raymond (January 23, 1922); two older sisters, Emma (August 11, 1916) and Lulu (August 22, 1919), and one younger sister, Mable (December 15, 1928).