if a man had several women with whom he had intercourse, and each breastfed a child, those children could not marry one another. Thus, when Ibn ʿAbbās was asked about this, he said: “The source of conception is the same.” This is the position of the four imams, based on the well-known hadith concerning Abū al-Quʿays, narrated by ʿĀʾishah in the two Sahīh collections.

A man is forbidden to marry his biological brother’s mother because she is either his own mother or his father’s wife, both of whom are forbidden to him. His breastfeeding brother’s mother, however, is neither his own mother nor his father’s wife, because her husband—the man to whom her milk is attributable—is not his father, either through blood kinship or breastfeeding.

If someone argues, “The Prophet, may Allah bless him and grant him peace, said, ‘Whatever is forbidden through blood kinship is also forbidden through breastfeeding.’ Since his biological brother’s mother is forbidden to him, his breastfeeding brother’s mother must likewise be forbidden,” we reply:

This is misleading and deceptive. Allah did not say, “Forbidden to you are your sisters’ mothers.” Rather, He said:

“Forbidden to you are your mothers.”

And He, Most High, said:

“And do not marry those women whom your fathers married.”

Thus, He forbade a man to marry his own mother or a woman married to his father, even if she is not his mother. The corresponding prohibition applies through breastfeeding, so he may not marry his mother through breastfeeding. As for a woman married to his father through breastfeeding, the well-known position among the imams is that she is forbidden to him. There is, however, disagreement concerning her, because this prohibition arises from affinity through marriage, not blood kinship or birth.

Whether she is forbidden is not the question under discussion here. If we say that a woman married to his father through breastfeeding is forbidden to him, we have upheld the hadith’s full general scope. As for his brother’s mother who is neither his own mother nor a woman married to his father, such a case does not exist in