Wet dreams are when a person orgasms involuntarily while they are sleeping because of a dream, which may or may not be erotic. They are called wet dreams because when a male has this type of dream, he may awaken with wet clothing or bedding. This is because semen, the fluid containing sperm, is released during ejaculation.

However, the same term is also used to refer to when a woman orgasms during sleep.Wet dreams are not caused by masturbation during sleep; they are a common experience for both sexes from puberty through adulthood.