What is the ruling on seminal discharge during sleep, and what should be done when in doubt about performing ghusl?

The emission of semen during sleep necessitates ghusl (ritual bath), even if the sleeper does not recall having a wet dream or experiencing pleasure. However, if one has a wet dream but no semen is emitted, or if there is doubt about its emission, then ghusl is not obligatory. If you doubt whether ghusl has occurred after its necessity has been established, then you must perform the ritual bath, because one's obligation is not discharged by a doubtful ghusl.