包皮環切術

In some parts and cultures of the world, it is customary or obligatory for minors of both sexes to be circumcised for religious reasons. Many believe that this practice is protected by the principle of freedom of religion. Others disagree, arguing that no right has precedence over the rights of bodily integrity of a child. Still others contend that freedom of religion only applies to belief, not action involving others. Female circumcision is prohibited in most western countries, and Sweden has restricted religious male infant circumcision. [4]

Recently there has been increasing cost-benefit analysis of the medical aspects of neonatal circumcision. Largely these have compared the average cost of neonatal circumcision, to the expected reduction in lifetime health costs, both financial and longevity, associated with reduced incidence of disease.

These studies have been conflicting but have formed the basis of public health policies. The American Academy of Pediatrics (1999) said the medical benfits of circumcision are not sufficient to recommend routine neonatal circumcision, but that it should be the decision of informed parents.[5]

The March 2005 Cochrane review concluded that while individual studies are of variable quality, there are clear indicators that circumcision can significantly reduce the chances of female-to-male HIV infection in an African population, when compared against an non-circumcised control group.[7] The review commented that the results of the three randomised controlled trials will be essential. The results of the first trial were published in November 2005, reporting 60% protection against HIV infection.[8] The World Health Organization stresses that the protective effect offered by male circumcision in Africa has to be confirmed by further studies, and is not reliable enough to replace, or undermine, sex education and safer sex practice as a means to combat AIDS. Currently, several more studies are under way to investigate the protective effect of circumcision against HIV infections, but the results will not be available until 2007.[9]

In 2000, Szabo and Short suggested that the foreskin's langerhans cells might provide an entry point for the virus, which Patterson et al confirmed in their 2002 study.[10] McCoombe et al found that these cells were close to the surface and that the layer of protective keratin above them was thin or nonexistent.[11] Langerhans cells, a part of the human immune system, can be infected by the HIV virus.[12]

There is some debate, even among the medical community, as to whether or not circumcision can prevent certain infectious diseases, including HIV. Some authors are of the opinion that the prepuce has an important immunological function, and that its removal increases the chances of infections^[1]. Their hypothesis has been criticised on technical grounds.[13] [14]

Several studies have shown that non-circumcised men are at greater risk of human papilloma virus (HPV) infection.[15] [16] [17] While most genital HPV strains are considered harmless, some can, but not necessarily do, cause genital warts or even cancer. One study found no statistically significant difference between men with foreskins for HPV infection than those who are circumcised, but did note a significantly higher incidence of HPV lesions and urethritis [18].

Circumcision reduces the amount of smegma produced by the body. Smegma, a transliteration of the Greek word σμήγμα for soap, is a combination of exfoliated (shed) , epithelial cells, transudated skin oils and moisture that can accumulate under the foreskin of males and within the female vulva area, with a characteristic strong odor and taste. Smegma is common to all mammals, male and female. While smegma is generally not believed to be harmful to health, the strong odour may be considered to be a nuisance giving the impression of lacking hygiene. In rare cases, accumulating smegma may play into causing balanitis.

The Royal Australasian College of Physicians and the Canadian Pediatric Society emphasize that an non-circumcised infants penis should be left alone and requires no special care. Attempts to forcibly retract the foreskin, e.g. to clean it, are painful, often injure the foreskin, and can lead to scarring, infections and pathologic phimosis. It is recommended that, while there is no special age where the foreskin should be retractible, once the foreskin becomes retractible, the child should gently wash it with soap and water. It has been suggested, however, that excessive washing of the foreskin and the glans will make infections such as balanitis more likely.

Non-circumcised children and men tend to have higher rates of various infections and inflammations of the penis, and of the foreskin, than circumcised men.[19] The reasons are unclear, but several hypotheses have been suggested:

• The foreskin may harbor bacteria and infect if it is not cleaned enough.[20]
• The foreskin may become inflamed if it is cleaned too often with soap.[21]
• The forcible retraction in boys can lead to infections.[22]

There are less invasive treatments than circumcision for posthitis (an inflamed foreskin) [23] and balanitis (inflammation of the glans) [24][25][26]. However, these are not as successful in treating balanitis xerotica obliterans (BXO) [27] [28] [29], which is harder to treat [30] [31].

Lichen sclerosus et atrophicus (LSA) produces a whitish-yellowish patch on the skin, and is not believed to be always harmful or painful, and may sometimes disappear without intervention. Some consider balanitis xerotica obliterans to be a form of LSA that happens to be on the foreskin, where it may cause pathological phimosis. Circumcision is believed to reliably reduce the threat of BXO. [32]

Penile cancer is cancer of the penis, i.e. on the glans or the foreskin. The lifetime risk is estimated to be 0.17% for a non-circumcised male, [33] and 80% of the cases are men over the age of 70. [34]

Circumcision and penectomy may be necessary to treat 陰莖癌. Less invasive treatments may include freezing of the tumor, chemical treatment, radiotherapy, and minimally invasive surgery. [35]

In 1998, the American Cancer Society labelled some claims about a relationship of circumcision with penile cancer misleading. It said:

However, the penile cancer risk is low in some non-circumcised populations, and the practice of circumcision is strongly associated with socio-ethnic factors, which in turn are associated with lessened risk. The consensus among studies that have taken these other factors into account is circumcision is not of value in preventing cancer of the penis. (1998, [36])

However, in 2005, the society said:

Recent studies have found that circumcised men are less likely to be infected with HPV, even after this risk is adjusted for differences in sexual behavior. Other studies suggest that circumcision may reduce the risk of more invasive forms of penile cancer. However, it is important that the issue of circumcision not distract the public's attention from avoiding known penile cancer risk factors – poor hygiene, having unprotected sex with multiple partners (increasing the likelihood of human papillomavirus infection), and cigarette smoking. (2005, [37])

While in another 2005 statement, they state:

In the past, circumcision has been suggested as a way to prevent penile cancer. This suggestion was based on studies that reported much lower penile cancer rates among circumcised men than among non-circumcised men. However, most researchers now believe those studies were flawed because they failed to consider other factors that are now known to affect penile cancer risk. (2005, [38])

Several studies and statistics have indicated that neonatal circumcision reduces the occurrence rate of UTI in male infants by a factor of about 10.[39] Some of these studies have been criticised in not taking other factors (especially for non-circumcision) into account.[40] A Swedish study found that the cumulative incidence of UTIs in boys under 2 years of age was 2.2%.[41]

The Canadian Pediatric Society poses the question of whether increased UTI and balanitis rates in non-circumcised male infants may be caused by forced premature retraction. [42]

主条目：Sexual effects of circumcision

The sexual effects of circumcision are controversial. Only a few studies have been made about the sexual function of the foreskin and the ridged band. Surveys however indicate that the majority of circumcised males are satisfied with their state.

There are few studies on partner preference for circumcised or non-circumcised penises, with inconclusive results; they are discussed more fully in the full article.

The American Academy of Pediatrics states "a survey of adult males using self-report suggests more varied sexual practice and less sexual dysfunction in circumcised adult men. There are anecdotal reports that penile sensation and sexual satisfaction are decreased for circumcised males."[43] The American Academy of Family Physicians states "no valid evidence to date, however, supports the notion that being circumcised affects sexual sensation or satisfaction."[44]

It has been variously proposed that circumcision began as a religious sacrifice, as a rite of passage marking a boy's entrance into adulthood, as a form of sympathetic magic to ensure virility, as a means of suppressing (or enhancing) sexual pleasure, as an aid to hygiene where regular bathing was impractical, as a means of marking those of lower (or higher) social status, as a means of differentiating a circumcising group from their non-circumcising neighbors, as a means of discouraging masturbation or other socially proscribed sexual behaviors, to remove "excess" pleasure, to increase a man's attractiveness to women, as a symbolic castration, as a demonstration of one's ability to endure pain, or as a male counterpart to menstruation or the breaking of the hymen. It is possible that circumcision arose independently in different cultures for different reasons.

Several hypotheses have been raised in explaining the American public's acceptance of infant circumcision as preventive medicine. The success of the germ theory of disease had not only enabled physicians to combat many of the postoperative complications of surgery, but had made the wider public deeply suspicious of dirt and bodily secretions. Accordingly, the smegma that collects under the foreskin was viewed as unhealthy, and circumcision readily accepted as good penile hygiene.[45] Secondly, moral sentiment of the day regarded masturbation as not only sinful, but also physically and mentally unhealthy, stimulating the foreskin to produce the host of maladies of which it was suspected. In this climate, circumcision could be employed as a means of discouraging masturbation.[46] All About the Baby, a popular parenting book of the 1890s, recommended infant circumcision for precisely this purpose. Interestingly, a 1410-man survey in the United States in 1992, Laumann found that circumcised men were more likely to report masturbating at least once a month.

With the proliferation of hospitals in urban areas, childbirth, at least among the upper and middle classes, was increasingly undertaken in the care of a physician in a hospital rather than that of a midwife in the home. It has been suggested that once a critical mass of infants were being circumcised in the hospital, circumcision became a class marker of those wealthy enough to afford a hospital birth.[47]

By the 1920s, advances in the understanding of disease had undermined much of the original medical basis for preventive circumcision. Doctors continued to promote it, however, as good penile hygiene and as a preventive for a handful of conditions local to the penis: balanitis, phimosis, and penile cancer.

Routine infant circumcision was taken up in the English-speaking parts of Canada, the United States and Australia, and to a lesser extent in New Zealand and the United Kingdom. Although it is difficult to determine historical circumcision rates, one estimate[48] of infant circumcision rates in the United States holds that 30% of newborn American boys were being circumcised in 1900, 55% in 1925, and 72% in 1950.

In 1949, a lack of consensus in the medical community as to whether circumcision carried with it any notable health benefit motivated the United Kingdom's newly-formed National Health Service to remove routine infant circumcision from its list of covered services. One factor in this rejection of circumcision may have been Douglas Gardiner's famous paper, The fate of the foreskin, which revealed, that for the years 1942–1947, about 16 children per year had died because of circumcision in England and Wales, a rate of about 1 per 6'000 performed circumcisions. [49] Since then, circumcision has been an out-of-pocket cost to parents, and the proportion of newborns circumcised in England and Wales has fallen to less than one percent.

In Canada, individual provincial health services began delisting circumcision in the 1980s. At present, only Manitoba pays for the procedure. The infant circumcision rate in Canada has fallen from roughly 50% in the 1970s to 13.9% in 2003. However, the figures varied from 29.5% on Prince Edward Island to zero in Labrador and Newfoundland. [50]

In South Korea, circumcision has rapidly gown in popularity following the establishment of the United States trusteeship in 1945 and the spread of American influence. More than 90% of South Korean high school boys are now circumcised, but the average age of circumcision is 12 years [51]. It is now considered to be an initiation into manhood, as well as a necessary hygienic measure, and is a source of great pride among the newly circumcised.

In South Africa circumcision has roots in several belief systems, and is performed most of the time to teen aged males :

"...The young men in the eastern Cape belong to the Xhosa ethnic group for whom circumcision is considered part of the passage into manhood... A law was recently introduced requiring initiation schools to be licensed and only allowing circumcisions to be performed on youths aged 18 and older. But Eastern Cape provincial Health Department spokesman Sizwe Kupelo told Reuters news agency that boys as young as 11 had died. Each year thousands of young men go into the bush alone, without water, to attend initiation schools. Many do not survive the ordeal..." [52].

The major medical societies in Britain, Canada, Australia and New Zealand do not support routine non-therapeutic infant circumcision. Major medical organizations in the United States state that parents should decide what is in their child's best interests, explicitly not recommending the procedure for medical reasons. Neonatal circumcision remains the most common pediatric operation carried out in the U.S. today.

Statistics from different sources give a somewhat different picture of the prevalence of circumcision in the United States.

The National Center for Health Statistics stated that the overall rate of neonatal circumcision was 64.3% in 1979 and 65.3% in 1999. However, the rate for white infants was 0.3% lower in 1999 than 1979 and the circumcision rate for black infants increased by 6.5% over this time [60]. Also, strong regional differences developed. In the West, circumcision declined from 63.9% to 36.7%, but this was counterbalanced by rises in the Midwest and South. [61] The decline in the West has been partly attributed to increasing births among Latin Americans, who usually do not circumcise [62].

A recent study, which used data from the Nationwide Inpatient Sample (a sample of 5-7 million of the nation's total inpatient stays, and representing a 20% sample taken from 8 states in 1988 and 28 in 2000), stated that circumcisions rose from 48.3% in 1988 to 61.1% in 1997.[63]

Figures from the Nationwide Hospital Discharge Survey (a sample of 270,000 inpatient stays), state that circumcision rates declined from 64.7% in 1980 to 59.0% in 1990, then rose to 64.1% in 1995, and fell again to 60.1% in 2002. Overall, the West saw the most significant change, declining from 61.8% in 1980 to 32.6% in 2002 (see Table 44, page 51 of the National Hospital Discharge Survey, 2002) [64].

Sixteen states no longer pay for the procedure under Medicaid [65]. One study in the Midwest of the US found that this had no effect on the newborn circumcision rate but it did affect the demand for circumcision at a later time.[66]