A wet dream — also called a nocturnal emission — is when a male ejaculates or "cums" while sleeping. During ejaculation, semen (the fluid that carries sperm) comes out of the penis. When you wake up you may notice a wet, sticky spot on your underwear that’s not pee. Wet dreams are a normal part of growing up and aren’t a health problem.

Wet dreams tend to happen during dreams that have sexual images. You may wake up from a wet dream or sleep through it. 

Wet dreams start during puberty. That’s when the body makes more of a hormone called testosterone. Wet dreams are a normal part of growing up and you can't stop them. They happen less often as you get older, but sometimes people have them as adults.

If you have any questions or concerns, talk to your doctor.