Margaret Jemison was born in Tunnel Springs (Monroe County), Alabama, in 1909, to Jim and Minnie Millender. She is beleived to be the sixth of ten children, with older and younger siblings Earnest, Coralie, Minnie, Rosa, Pinkie, Vince, Jimmie, Andrew, and Georgia.
As the story goes, the original family name was Millender. For reasons not clear, possibly the safety of the family; Magaret's father relocated the family overnight to Baldwin County. Subsequently, some of the family changed their name to Jemison.