The Ruling on Marrying the Sister of a Sister from a Foster Relationship
Question:
I have cousins from a paternal uncle and their elder sister was breast-fed by my mother, and I have a sister who is older than I, who was breast-fed by their mother. After the passage of time, I proposed marriage to my paternal uncle's youngest daughter, who was not breast-fed by my mother. Is it permissible for me to be united (in marriage) with her, bearing in mind that I was not breast-fed by my uncle's wife?
Answer:
If the matter is as you have stated in question, then there is no sin in you marring your paternal uncleýs daughter, who was not breast-fed by your mother, when there is no other foster relationship between you and her, nor any ties of kinship which would make her forbidden to you. And Allah is the Granter of success.
Source:
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah Darussalam Vol:5 no.226
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