✅Answer: Please pay attention to the following narrations:

1 بُرَيْدٍ الْعِجْلِيِّ عن أَبِي جَعْفَر فِي حَدِيثٍ أَنَّ رَسُولَ اللَّهِ قال: يَحْرُمُ مِنَ الرَّضَاعِ مَا يَحْرُمُ مِنَ النَّسَب

📚 Faqih, Vol. 3, p. 475

Imam Al-Baqir (peace be upon him) said in a hadith: 'The Messenger of Allah (peace be upon him and his family) said: The Mahramiyyah that is established through lineage is also established through suckling and breastfeeding!'

2 زيادبن سوقة قال: قُلْتُ لِأَبی جعفر هَلْ لِلرَّضَاعِ حَدٌّ يُؤْخَذُ بِهِ فَقَالَ لَا يُحَرِّمُ الرَّضَاعُ أَقَلَّ مِنْ يَوْمٍ و لَيْلَةٍ أَوْ خَمْسَ عَشْرَةَ رَضْعَةً مُتَوَالِيَاتٍ مِنِ امْرَأَةٍ وَاحِدَةٍ مِنْ لَبَنِ فَحْلٍ وَاحِدٍ لَمْ يَفْصِلْ بَيْنَهَا رَضْعَةُ امْرَأَةٍ غَيْرِهَا فَلَوْ أَنَّ امْرَأَةً أَرْضَعَتْ غُلَاماً أَوْ جَارِيَةً عَشْرَ رَضَعَاتٍ مِنْ لَبَنِ فَحْلٍ وَاحِدٍ و أَرْضَعَتْهُمَا امْرَأَةٌ أُخْرَى مِنْ فَحْلٍ آخَرَ عَشْرَ رَضَعَاتٍ لَمْ يَحْرُمْ نِكَاحُهُمَا

📚 Al-Tahdhib, Vol. 7, p. 315

Ziyad ibn Suqah says: I said to Imam Al-Baqir (peace be upon him): 'Is there a limit for suckling that is to be taken into consideration?' He said: 'Suckling for less than a day and a night or 15 consecutive sucklings from a single woman, from the milk resulting from a single husband, that is not interrupted by the suckling of another woman, does not make them unmarriageable (does not create Mahramiyyah).'

So if a woman breastfeeds a boy or a girl ten times from the milk of a single husband, and another woman also breastfeeds them ten times from the milk resulting from another husband, their marriage to each other is not forbidden!

3 ابْنِ أَبِي يَعْفُورٍ قَالَ: سَأَلْتُهُ عَمَّا يُحَرِّمُ مِنَ الرَّضَاعِ قَالَ إِذَا رَضَعَ حَتَّى يَمْتَلِئَ بَطْنُهُ فَإِنَّ ذَلِكَ يُنْبِتُ اللَّحْمَ وَ الدَّمَ وَ ذَلِكَ الَّذِي يُحَرِّمُ

📚 Al-Tahdhib, Vol. 7, p. 316

Ibn Abi Ya'fur says: I asked (Imam Al-Sadiq, peace be upon him) about what amount of suckling establishes Mahramiyyah;

He said: 'If the child sucks until his stomach is full, this is the amount that causes flesh and blood to grow, and this is what establishes Mahramiyyah!'

4 عن أَبِي عَبْداللَّه قال: الرَّضَاعُ الَّذِي يُنْبِتُ اللَّحْمَ وَ الدَّمَ هُوَ الَّذِي يَرْضِعُ حَتَّى يَتَضَلَّعَ وَ يَتَمَلَّى وَ يَنْتَهِيَ نَفْسُهُ

📚 Al-Tahdhib, Vol. 7, p. 316

Imam Al-Sadiq (peace be upon him) said: 'The suckling that causes flesh and blood to grow is when the child sucks until he is full and satisfied and he himself stops sucking!'

5 حماد بن عثمان قال: سَمِعْتُ أَبَا عَبْداللَّه يَقُولُ لَا رَضَاعَ بَعْدَ فِطَامٍ قُلْتُ و مَا الْفِطَامُ قَالَ الْحَوْلَيْنِ الَّذِي قَالَ اللَّهُ عَزَّوَجَلَّ

📚 Al-Kafi, Vol. 5, p. 443

Hammad says: I heard Imam Al-Sadiq (peace be upon him) say: 'There is no suckling (that establishes Mahramiyyah) after the child has been weaned!'

I said: 'What is weaning?'

He said: 'The two years that Allah, the Almighty and Glorious, has mentioned!'

✅ Meaning verse 233 of Surah Al-Baqarah:

وَالْوَالِدَاتُ يُرْضِعْنَ أَوْلَادَهُنَّ حَوْلَيْنِ كَامِلَيْنِ لِمَنْ أَرَادَ أَن يُتِمَّ الرَّضَاعَةَ

'Mothers suckle their children for two full years, for those who wish to complete the suckling period.'

6 يونس بن يعقوب عن أَبي عبداللَّه قال: سَأَلْتُهُ عن امْرَأَةٍ دَرَّ لَبَنُهَا مِنْ غَيْرِ وِلَادَةٍ فَأَرْضَعَتْ جَارِيَةً و غُلَاماً مِنْ ذَلِكَ اللَّبَن هَلْ يَحْرُمُ بِذَلِكَ اللَّبَن ما يَحْرُمُ مِنَ الرَّضَاع قَالَ لَا

📚 Al-Kafi, Vol. 5, p. 446

Yunus says: I asked Imam Al-Sadiq (peace be upon him) about a woman whose milk flows without giving birth, so she breastfeeds a boy and a girl from that milk. Does this milk establish unmarriageability similar to what is established by suckling? He said: 'No!'

✅ Based on the above narrations and others, the establishment of the prohibition of marriage and the creation of Mahramiyyah between two people through suckling has various conditions, some of which are:

1 The suckling must be within the two-year period that the mother breastfeeds her child.

2 The suckling must be at least one day and a night or 15 consecutive sucklings.

3 The child, at each instance, must suckle until his stomach is full and satisfied and he himself stops sucking, because such suckling is what causes the growth of flesh and blood and the strengthening of bones.

4 The child must not be breastfed by another woman in between.

5 Suckling is only established between those whose 'fahl', meaning the man who caused the pregnancy and the milk, is one and the same.

6 The milk must have been produced as a result of childbirth.

✅ If the above conditions and other necessary conditions are met, if a woman breastfeeds another person's child, that woman becomes his foster mother, and her children become his foster siblings, and according to narration 1 and others, it establishes Mahramiyyah and the prohibition of marriage just like her own child.