According to the unofficial timeline of Don Rosa, Daisy was born in 1920. According to Rosa, Daisy is the sister of Donald's brother-in-law – Daisy's brother had married Donald's twin sister, Della Duck, and together, the two became the parents of Huey, Dewey, and Louie Duck. This is his explanation of why the triplets tend to call her "Aunt Daisy" while no such courtesy is given to Gladstone Gander for example. Don Rosa has said that he considers Donald and Daisy to be nonrelated and that Duck simply is the Duckburg universe equal to Smith, being a common surname.