Hazrat Ali (may Allah be pleased with him) said that madhiy (pre-seminal fluid) used to be discharged from me. I said to Miqdad to ask the Messenger of Allah about this matter because the daughter of the Prophet was married to me, so I felt shy to ask this question myself. Miqdad asked, and the Prophet said: "Every adult man has madhiy discharged from him. If it is semen (mani), then ghusl (full ritual bath) is obligatory; if it is madhiy, then wudu (ablution) is obligatory."