Heredity

"Heredity" is a science fiction short story by the American writer Isaac Asimov. Asimov wrote the story, his twenty-third, in August 1940 under the title "Twins". It was rejected by John W. Campbell, editor of Astounding Science Fiction, on 29 August, and accepted by Frederik Pohl on 4 September. It appeared in the April 1941 issue of Astonishing Stories under the title "Heredity" and was reprinted in the 1972 collection The Early Asimov. Heredity was the second Asimov story to receive a cover illustration.