ANSWER: If a person wakes and finds wetness on his clothing, he falls within of one three categories:
1. That he is positive it is semen, in which case, it is obligatory for him to perform ghusl, whether he remember having wet-dream or not.
2. That he is positive it is not semen, in which case, it is not obligatory for him to perform ghusl, but he must wash what it is that has affected him, because the ruling on it is the ruling of urine.
3..That he is unaware whether or not it is semen; in that case it requires elaboration: If he remembers that he had a sexual dream while he was asleep, he must regard it as semen and perform ghusl, according to the hadith of Umm Salamah [RA], who asked the Prophet [peace and blessings be upon him] about what a woman should do if she sees in her dreams what a man sees [i.e. wet-dreams], should she perform ghusl? He replied : Yes, if she sees some liquid. [Muslim]
If he did not see anything in his sleep, and if he was thinking about sexual intercourse before he slept, he should regard it as prostate fluid. If he was not thinking about sexual intercourse before he slept, then this is an area of differing: It has been said that he must perform ghusl in order to be on the safe side, and it has been said that it is not obligatory for him to do so, and it is the correct opinion, because the basic principle is freedom from liability.
This article was culled from the publications of Deen Communication Limited