Hazrat Tawus (may Allah have mercy on him) said: "If a man has a wife and his wife's daughter, then if the daughter was born before her mother (became his wife), it is permissible for his son to marry her. If she was born after, then it is disliked." Hazrat Mujahid (may Allah have mercy on him) did not see any issue whether it was before or after. Hazrat Abu Uthman (may Allah have mercy on him) said: "The statement of Mujahid (may Allah have mercy on him) is reliable."
Hadith Referenceسنن سعید بن منصور / كتاب النكاح / 2196
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم:، 1019، وابن أبى شيبة فى «مصنفه» برقم: 18017»