Yahya related to me from Malik from Ibn Shihab from Urwa ibn az-Zubayr that Umm Sulayman said to the Messenger of Allah, may Allahbless him and grant him peace, "Should a woman do ghusl when sheexperiences the same as a man in her sleep?" The Messenger of Al lahsaid to her, "Yes, she should do ghusl. "A'isha said to her, "Shame onyou! 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 righthand be full of dust. From where does family resemblance come?"
USC-MSA web (English) reference: Book 2, Hadith 86
Arabic reference: Book 2, Hadith 116