Monroe was born on June 1, 1926, as Norma Jeane Mortenson (soon after changed to Baker), the third child born to Gladys Pearl Baker (née Monroe) (May 27, 1902 – March 11, 1984). Monroe's birth certificate names the father as Martin Edward Mortensen with his residence stated as "unknown".

The name Mortenson is listed as her surname on the birth certificate, although Gladys immediately had it changed to Baker, the surname of her first husband and which she still used. Martin's surname was misspelled on the birth certificate leading to more confusion on who her actual father was.

Marilyn Monroe's Family Tree