The Kentucky birth index lists two delayed birth certificates for which Monnie is probably the mother: Marjorie A. Seals, born 8 Oct 1937 in Breathitt Co. (a misindexing of Rowan Co.), mother’s maiden name Monnie Fraley, registered in 1956, and Marjorie Ann Carter born 8 Oct 1937 in Rowan Co., mother’s maiden name Monnie Fraley, registered 6 Oct 1977.

This looks like someone who was changing her official surname, perhaps to a stepfather’s and then back to her birth father’s, or something like that. I cannot find any Monnie Carter or Monnie Seals in the 1920 or 1930 census.