Prostate

Prostate

It is a small gland that is part of the male reproductive system. It's supposed to be about the shape and size of a walnut.
It rests below your bladder and in front of your rectum. It surrounds part of the urethra, the tube in your penis that carries pee from your bladder.
The prostate helps make some of the fluid in semen, which carries sperm from your testicles when you ejaculate.

Causes
By the time you reach age 40, your prostate might have gone from the size of a walnut to the size of an apricot. By the time you reach 60, it might be the size of a lemon.
Because it surrounds part of the urethra, the enlarged prostate can squeeze that tube. This causes problems when you try to pee. Typically, you won't see these problems until you're 50 or older, but they can start earlier.
You might hear a doctor or nurse call this condition benign prostatic hyperplasia, or BPH for short. It is not cancerous.