Circumcision of males involves removing the fold of skin that normally covers the glans penis.
Although no consensus exists among scholars regarding the origins of circumcision, some have suggested that this procedure likely originated in Egypt some 15,000 years ago and that its practice later spread throughout the world during prehistoric human migrations. Egyptian mummies and wall carvings discovered in the 19th century offer some of the earliest records of circumcision dating this procedure to at least 6000 years BC. However, other authors believe that circumcision developed independently in different cultures. For example, on his arrival to the New World, Columbus found that many of the natives were already circumcised.
Many cultures have historically used circumcision for hygienic reasons while others performed it as a rite of passage to manhood, as a mark of cultural identity (similar to a tattoo), or as a ceremonial offering to the gods. Ritual circumcisions in Middle Eastern cultures have been practiced for at least 3000 years. Late in the 19th century, this ancient ritual evolved into routine medical practice influenced by reports that associated it with miraculous cures for hernias, paralysis, epilepsy, insanity, masturbation, headache, strabismus, rectal prolapse, hydrocephalus, clubfoot, asthma, enuresis, and gout.
Routine neonatal circumcision has become a controversial issue in the past 2 decades as many of the previously accepted medical indications have come under considerable scrutiny. Because neonatal circumcision poses both potential benefits and risks and because the procedure is not necessary for a child's well-being, the American Academy of Pediatrics (AAP) Task Force on Circumcision in its latest policy statement in 1999 affirms that "existing scientific evidence demonstrates potential benefits of newborn male circumcision; however, these data are not sufficient to recommend routine neonatal circumcision."  As a consequence, parents should be appropriately counseled so that they can make an informed choice and decide whether a circumcision is in the best interest of their child.
Bossio et al conducted a review of peer-reviewed medical journal articles to assess the state of circumcision research, as that research applies to North American populations.  Their review uncovered considerable gaps within the current literature on circumcision, including a need for empirically based studies to address questions about circumcision and sexual function, penile sensitivity, the effect of circumcision on men's sexual partners, reasons for circumcision, the effects of age at circumcision (particularly with regard to neonatal circumcision), and the need for objective research outcomes. The investigators commented that such research is needed to inform policy makers, healthcare professionals, parents, and others with regard to the decision to perform routine circumcision on male neonates in North America. 
The penile skin is continuous with that of the lower abdominal wall. Distally, the penile skin is confluent with the smooth, hairless skin covering the glans. At the corona, it is folded on itself to form the prepuce (foreskin), which overlies the glans. The subcutaneous connective tissue of the penis and scrotum has abundant smooth muscle and is called the dartos fascia, which continues into the perineum and fuses with the superficial perineal (Colle) fascia. In the penis, the dartos fascia is loosely attached to the skin and deep penile (Buck) fascia and contains the superficial arteries, veins, and nerves of the penis. For more information about the relevant anatomy, see Penis Anatomy.
The prepuce, a fold of skin that covers the glans penis, is lined up by an external keratinized layer and an internal mucosal layer. The pouch thus created can collect desquamated epithelial cells forming the so-called keratin pearls in infants and toddlers (which are not infectious in nature). In adolescence, cellular debris and local secretions collect in the form of smegma if the penis is not cleaned regularly. The prepuce provides protection to the glans from dryness and keratinization. Innervation of the prepuce is complex, the dorsal nerve of the penis and branches of the perineal nerve provide somatosensory input, whereas autonomic innervation comes primarily from the pelvic plexus.
In the United States, accurate estimates of the rate of neonatal circumcisions are limited. The frequency of circumcision varies depending on geographic location, religious affiliation, and socioeconomic classification. One study showed differences in neonatal circumcision rates among racial and ethnic groups: 81% in whites, 65% in African-Americans, and 54% in Hispanics.
According to data from the National Hospital Discharge Survey, 1.2 million (65.3%) babies were circumcised in the United States in 1999, making this the highest rate of routine neonatal circumcision among developed nations. Healthcare coverage has and will continue to affect the rates of routine neonatal circumcision. As of 2004, 13 states had terminated Medicaid funding for neonatal circumcisions. At present, approximately 70% of obstetricians, 60% of family practitioners, and 35% of pediatricians practice newborn circumcision.
Circumcision applies only to male individuals.