Nikah with a Uterine Sister and with a Consanguine Sister

Question

(1) Zayd died, leaving a son and a wife. Afterwards his wife contracted nikah with ‘Umar, and a daughter was born to her from ‘Umar. In this case, will the nikah of Zayd’s son with ‘Umar’s daughter be valid or not? (2) Bakr had a son from his first wife, and then Bakr’s wife died, so Bakr married a second time. A daughter was born from the second wife. Will the nikah between these two be valid or not?

Answer

(1) In the case asked about, Zayd’s son and ‘Umar’s daughter have one mother; so these two are brother and sister, and therefore their nikah with each other is not valid. (2) These two have one father, so their nikah too is impermissible.

Source: Fatawa Mahmudiyya

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