Source: Fatāwā Amunpuri by Shaykh Ghulām Muṣṭafā Ẓahīr Amn Pūrī
✿ Question:
Can a man marry a girl who was breastfed by his sister-in-law (his brother’s wife)?
✿ Answer:
No, marriage with such a girl is not permissible, as she is considered his foster niece (رضاعی بھتیجی).
This is because she becomes the foster daughter of his brother.
❀ Quranic Evidence:
**
وَبَنَاتُ الْأَخِ
**
“…And [forbidden to you in marriage are] your brother’s daughters.”
📚 Surah al-Nisā’ (4:23)
This ruling applies to both biological and foster nieces, as relationships made unlawful by blood are also unlawful through breastfeeding.
❀ Prophetic Example:
It was suggested to the Prophet ﷺ that he marry the daughter of Ḥamzah ibn ʿAbd al-Muṭṭalib. The Prophet ﷺ responded:
“She is my foster niece.”
📚 Ṣaḥīḥ al-Bukhārī: 5100
✔ Summary:
✦ A girl who is breastfed by a man’s brother’s wife becomes his foster niece.
✦ Just as biological nieces are prohibited for marriage, so are foster nieces.
✦ Therefore, marriage with her is not allowed under Islamic law.
