Wet dreams

A nocturnal emission, informally known as a wet dream, is a spontaneous orgasm during sleep that includes ejaculation for a male, or vaginal wetness or an orgasm (or both) for a female. Nocturnal emissions are most common during adolescence and early young adult years, but they may happen any time after puberty. It is possible for men to wake up during a wet dream or simply to sleep through it, but for women, some researchers have added the requirement that she should also awaken during the orgasm and perceive that the orgasm happened before it counts as a wet dream. Vaginal lubrication alone does not mean that the female had an orgasm.

Due to the difficulty in collecting ejaculate produced during nocturnal emissions, relatively few studies have examined its composition. In the largest study, which included nocturnal emission samples from 10 men with idiopathic anejaculation, the semen concentration was equivalent to samples obtained from the same men by penile vibratory stimulation, although the proportions of sperm which were mobile and which were of normal morphology were higher in the nocturnal emission specimens.

In a detailed study, men and women reported that approximately 8% of their everyday dreams contain some form of sexual-related activity. Four percent of sex dreams among both men and women resulted in orgasms.

The frequency of nocturnal emissions is highly variable. Some reported that it is due to being sexually inactive for a period of 1–2 weeks, with no engagement in either intercourse or masturbation. Some males have experienced large numbers of nocturnal emissions as teenagers, while others have never experienced one. In the U.S., 83% of men will experience nocturnal emissions at some time in their life. For males who have experienced nocturnal emissions the mean frequency ranges from 0.36 times per week (about once every three weeks) for single 15-year-old males to 0.18 times per week (about once every five-and-a-half weeks) for 40-year-old single males. For married males the mean ranges from 0.23 times per week (about once per month) for 19-year-old married males to 0.15 times per week (about once every two months) for 50-year-old married males. In some parts of the world nocturnal emissions are more common. For example, in Indonesia surveys have shown that 97% of men experience nocturnal emissions by the age of 24.

Some males have the emissions only at a certain age, while others have them throughout their lives following puberty. The frequency with which one has nocturnal emissions has not been conclusively linked to frequency of masturbation. Alfred Kinsey found there may be "some correlation between the frequencies of masturbation and the frequencies of nocturnal emissions. In general the males who have the highest frequencies of nocturnal emissions may have somewhat lower rates of masturbation."

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