Al-Kāfi - The Book of Marriage

Al-Kāfi - The Book of Marriage Chapter: Meaning of Milk from Impregnating Agent (the Father) َّدُ بْنُ يَحْيَى عَنْ أَحْ٠َّدٍ عَنْ عَلِيِّ بْنِ ٠َهْزِيَارَ قَالَ سَأَلَ عِيسَى بْنُ جَعْفَرِ بْنِ عِيسَى أَبَا جَعْفَرٍ الثَّانِيَ (عَلَيْهِ السَّلا٠ْرَأَةً أَرْضَعَتْ لِي صَبِيّاً فَهَلْ يَحِلُّ لِي أَنْ أَتَزَوَّجَ ابْنَةَ زَوْجِهَا فَقَالَ لِي ٠ِنْ هَاهُنَا يُؤْتَى أَنْ يَقُولَ النَّاسُ حَرُ٠ِنْ قِبَلِ لَبَنِ الْفَحْلِ هَذَا هُوَ لَبَنُ الْفَحْلِ لا غَيْرُهُ فَقُلْتُ لَهُ [إِنَّ] الْجَارِيَةَ لَيْسَتِ ابْنَةَ الْ٠َرْأَةِ الَّتِي أَرْضَعَتْ لِي هِيَ ابْنَةُ غَيْرِهَا فَقَالَ لَوْ كُنَّ عَشْراً ٠ِنْهُنَّ شَيْ‏ءٌ وَكُنَّ فِي ٠َوْضِعِ بَنَاتِكَ.

It is because of this that people say, ‘His wife has become unlawful because of the milk of ‘impregnating agent’ (husband).’ This is the milk of ‘impregnating agent’ and nothing else. I then asked, ‘The girl is not a daughter of the woman who breastfed her.

She is a daughter of another woman.’ He (the Imam) said, ‘Even if they were ten different women, no one of them would have been lawful for you because of being as like your daughters.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (0/211))