Her Milk-Uncle
Question: I would like to marry my maternal aunt’s daughter, but I have learned that this aunt was nursed by my mother along with me. Is marriage permissible in such a case or not? Please advise, and may Allah bless you.
Answer: If the nursing you referred to amounted to five separate sucklings or more and occurred within the first two years of life, then it is not lawful for you to marry this girl. You are her milk-uncle: her mother was nursed by your mother, making her mother your milk-sister, and her daughter therefore becomes the daughter of your milk-sister. Consequently she is forbidden to you. Allah, exalted is He, knows best.
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Marriage Permissible
Question: I have a paternal cousin who is of marriageable age and I wish to marry her. The issue is that her brother, who is also my cousin, was nursed by my mother when she was nursing my elder sister. Does this nursing invalidate my prospective marriage to his sister according to the Sacred Law? Please advise, and may Allah reward you with goodness.
Answer: There is no objection to your marrying your cousin, even though her brother was nursed by your mother. This has no effect as long as she herself was not nursed by your mother and you were not nursed by hers. There is therefore no milk-relation between the two of you, and it is permissible for you to marry her. Allah, exalted is He, knows best.