Julia Camoys Stonor was born Julia Maria Christina Mildred Stonor, the eldest daughter and first child of Ralph Robert Watts Sherman Stonor, 6th Baron Camoys of Stonor Park and Newport, Rhode Island, USA (1913-1976), by his wife (Mary) Jeanne Stourton (1913-1987).
Legally, Jeanne Stourton's maternal grandfather, was the paternal grandson of Charles Stourton, 19th Baron Stourton.