What is the ruling on the marriage of the first wife’s daughter to her paternal cousin (the first wife’s son) in the event that the second wife breastfed the first wife’s daughter, her granddaughter, and her grandson, and is the first wife’s daughter considered the paternal aunt of her nephew through رضاعة (radha'a - fosterage)?
Source: FtawySummary from Ftawy's records · added here Sep 2, 2026
What is established by lineage is also established by fosterage, as the Prophet, peace and blessings be upon him, said: "What is forbidden by lineage is forbidden by fosterage."
Thus, whoever is suckled by a woman becomes her son and the son of her husband, the owner of the milk. Therefore, the granddaughter mentioned is considered a paternal aunt by fosterage to her paternal cousin, because she is her father's sister by fosterage. Hence, she is not permissible for him.
However, the fosterage that establishes prohibition must consist of five or more full sucklings.
Summary from Ftawy's records · added here
Reviewed by El Fatwa's sharia committee.
Read the full answer on Ftawyhttps://ftawy.com/en/questions/178446
Where this answer came from
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- Ftawy
- Original fatwa ID
- 178446
- Added here
- . This is when the answer was added to El Fatwa, not the fatwa's date.
- Text
- Summary from Ftawy's records, reviewed by El Fatwa's sharia committee.
- Read the full ruling
- Read the full answer on Ftawy