Source: Fatāwā Amunpuri by Shaykh Ghulām Muṣṭafā Ẓahīr Amn Pūrī
✿ Question:
Hindah has six children — three sons and three daughters. She also breastfed the son of her maternal cousin. Is it permissible for this foster son to marry Hindah’s granddaughter?
✿ Answer:
It is not permissible for Hindah’s foster son to marry Hindah’s granddaughter, because he is her foster maternal uncle (رضاعی ماموں).
Just as a biological uncle is forbidden from marrying his niece, a foster uncle is also forbidden from marrying his foster niece.
❀ Quranic Evidence:
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وَبَنَاتُ الْأُخْتِ
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“…And [forbidden to you in marriage are] the daughters of your sisters.”
📚 Surah al-Nisā’ (4:23)
This includes both biological and foster nieces, because all relationships that are prohibited due to lineage are also prohibited through breastfeeding.
✔ Summary:
✦ A man breastfed by a woman becomes her son through Riḍāʿah.
✦ He is therefore the foster maternal uncle of all her grandchildren.
✦ Consequently, he cannot marry her granddaughter, as such a marriage is haram — exactly like with biological relationships.
