her brothers who were not breastfed by that woman. A man may therefore marry his sister’s sister if he was not breastfed by her mother and she was not breastfed by his mother. The nursed girl, however, may not marry any son of the woman who breastfed her. The imams agree on this.

The underlying principle is that the nursing woman becomes the nursed girl’s mother, so her children become forbidden to the girl in marriage. The nursing woman’s brothers and sisters become the girl’s maternal uncles and aunts. The man to whom the milk is attributed becomes her father, and his children, whether by that woman or another, become her siblings. His brothers and sisters become her paternal uncles and aunts. The nursed child, his children and his grandchildren are regarded as offspring of the nursing woman and the man whose intercourse caused the milk to flow. As for the nursed child’s biological brothers, sisters, father and mother, they remain outside this kinship: no marriage prohibition arises for them from this breastfeeding. All four imams agree on this, although they differ over other matters.

He—may Allah Most High have mercy on him—was asked:

“Two men were breastfed by the same woman, and one of them had a daughter. May the other marry her?”

He replied:

If a child is breastfed by a woman five times within his first two years, he becomes her son, and all her children become his siblings, whether she gave birth to them before or after the breastfeeding. Breastfeeding establishes the same marriage prohibitions as birth, according to the Sunnah of the Messenger of Allah