Is it permissible for the son of a man, who was suckled by his father’s wife, to marry the sister of that man, if the suckling occurred before the father’s marriage to the girl’s mother?
It is not permissible for a man to marry his paternal sister if he was nursed by his father's wife with her milk, because by doing so, he becomes a brother to her and to all his father's children through suckling, based on the Almighty's saying: "And your sisters through suckling," and the Prophet's (peace be upon him) saying: "Suckling prohibits what lineage prohibits."
Summarized from the full answer at Ftawy · reviewed Sep 2, 2026
Read the full answer on Ftawyhttps://ftawy.com/en/questions/110508