The glans penis is the head of the penis. Also known simply as the glans, this part of the male anatomy has a slit-like opening called the urethra from which urine, pre-ejaculate and sperm is passed. Many anatomists have generalized that the glans penis is the most sensitive area of the male genitalia and thus the most reasonable place for sexual stimulation. Though preferences vary by person, the glans is anatomically a center for many nerve endings, which makes it similar to the female clitoris. The frenulum of prepuce of penis, or simply "frenulum," is also located directly beneath the glans.
The exact shape of the glans varies in men by the intensity of their arousal. In some men, the glans penis is much wider than the shaft of the penis, creating a "mushroom" appearance. In others, it is narrower.
The overall appearance of the glans penis in men also varies by whether or not they have been circumcised. In uncircumcised men, the foreskin is left intact. When the penis is flaccid, the foreskin covers the glans penis. In uncircumcised men, the glans is kept protected and oiled by the foreskin, which spreads lubrication and a waxy layer over it. When an uncircumcised man is aroused, the glans enlarges and the foreskin draws back so that it is fully exposed.
In circumcised men, the glans of the penis is left exposed. Without the covering of the foreskin, it is often drier than it is on an uncut male. There is also scarring around the base of the glans where the foreskin was removed. When a circumcised man becomes erect, his glans simply becomes enlarged, already being uncovered.
According to the World Health Organization (WHO), 30% of men in the world are circumcised. The method has become controversial in tandem with concern over female genital mutilation. Proponents of circumcision cite tradition, as well as studies pointing to a decreased risk for human immunodeficiency virus (HIV) for men whose foreskin has been removed. Those against circumcision point out that after the process, the glans is left uncovered and can lose a great deal of its sensitivity, limiting sexual response.
Circumcised infants are also at a greater risk for infection. When wearing diapers, their glans and urethra are unprotected from feces and urine. In some cases, the urethra will actually narrow to the extent that it may have to be surgically re-enlarged.