The permissibility of combining marriage with a woman and having relations with her stepdaughter (Rabiibah).
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
The majority of scholars rule that combining marriage to a woman and having relations with her stepdaughter is permissible, with no objection. This practice was done by Abdullah ibn Ja'far and Abdullah ibn Safwan ibn Umayyah. The general body of jurists adhere to this view, except for Al-Hasan, 'Ikrimah, and Ibn Abi Layla.
Supporting text
Al-Hasan, 'Ikrimah, and Ibn Abi Layla reported the dislike (Karahah) of this combination because if the stepdaughter were a male, the aunt (the wife) would be forbidden to him, thus likening the situation to marrying a woman and her paternal aunt. The proof for permissibility is the statement of God Almighty: {And lawful to you are all those beyond those mentioned} (Quran 4:24). Furthermore, there is no direct blood relationship between the wife and the stepdaughter, making them analogous to two unrelated women. The prohibition of combining certain relatives is due to fear of severing close kinship ties between those related by blood, which does not apply here.