Musnad Abu Ya'la al-Mawsili 115:79

Abu Bakr narrated to us, Yazid bin Harun narrated to us, from Sa'id bin Abi 'Aruba, from Qatadah, from Anas: That Umm Sulaym asked the Prophet, peace and blessings of Allah be upon him, about a woman who sees in her dream what a man sees. The Messenger of Allah, peace and blessings of Allah be upon him, said: "If a woman sees that, and she discharges fluid, then she must perform ghusl (ritual bath)." Umm Sulaym said: "O Messenger of Allah, does this happen?" He said: "Yes. The man's fluid is thick and white, and the woman's fluid is thin and yellow. Whichever of them precedes or rises above the other, the child will resemble that one."