A Negro once came to Hazrat Omar (RA). His wife was also of black colour. The Negro complained to Hazrat Omar (RA) that he and his wife were both of black coloured, but his wife in contrast to their colour had given birth to a child of red colour. He also said that his wife had obviously committed adultery with some man who was of the colour of the child.
Hazrat Omar (RA) could not decide the case and referred the matter to Hazrat Ali (A) who in turn asked the Negro: “ If I ask you a question, will you answer it correctly ?”
The Negro replied: “ Yes Sir, by all means and quite correctly if I could.”
Hazrat Ali (A) asked the negro:“Did you ever go to your wife i.e., had you ever had intercourse with her during her monthly course” ?
The negro replied :“Yes, Sir, I think I have.”
Hazrat Ali (A) said to him:“The colour of the child is the result of that very act of yours. You are, therefore, yourself at fault and not your wife.” The Negro was ashamed and went away. (Turuq-i-Hikmia by Ibne Qaiyyum: p. 47).