Maliks Muwatta Book 2, Hadith Number 86.
Section : Ghusl of a Woman when She Experiences the Same as a Man in Her Sleep.
Yahya related to me from Malik from Ibn Shihab from Urwa ibn az-Zubayr that Umm Sulayman said to the Messenger of Allah, may Allah bless him and grant him peace, “Should a woman do ghusl when she experiences the same as a man in her sleep?” The Messenger of Allah said to her, “Yes, she should do ghusl. “A’isha said to her, “Shame on you! Does a woman see that?” (i.e. a liquid.) The Messenger of Allah, may Allah bless him and grant him peace, said to her, “May your right hand be full of dust. From where does family resemblance come?”