Question:

Some people claim that Fatimah (a.) is the only daughter of the Messenger (s.), does the author of Kitab Al-Irshad agree with this belief?

Answer:

Muhammad Ibn Muhammad Al-Mufid writes:

إن زينب ورقية كانتا ابنتي رسول الله صلى الله عليه وآله والمخالف لذلك شاذ بخلافه فأما تزويجه لهما بكافرين فإن ذلك كان قبل تحريم مناكحة الكفار

“Zainab and Ruqayyah were both the daughters of the Messenger (s.) and whoever objects to this, is a strange oddball in regard to his objection, and as for the marriage of his two daughters to two disbelievers, this happened before the prohibition of marriage to disbelievers.” [Al-Masa’il-ul-Ukbariyyah, page 120]