Sexual effects of circumcision

The sexual effects of male circumcision are not well understood and researchers' findings are often contested.

Glans sensitivity
Masters and Johnson (1966) reported: "Routine neurologic testing for both exteroceptive and light tactile discrimination were conducted on the ventral and dorsal surfaces of the penile body, with particular attention directed toward the glans. No clinically significant difference could be established between the circumcised and the uncircumcised glans during these examinations." In January 2007, The American Academy of Family Physicians (AAFP) stated "The effect of circumcision on penile sensation or sexual satisfaction is unknown. Because the epithelium of a circumcised glans becomes cornified, and because some feel nerve over-stimulation leads to desensitization, many believe that the glans of a circumcised penis is less sensitive. Opinions differ about how this decreased sensitivity, which may result in prolonged time to orgasm, affects sexual satisfaction. An investigation of the exteroceptive and light tactile discrimination of the glans of circumcised and uncircumcised men found no difference on comparison. No valid evidence to date, however, supports the notion that being circumcised affects sexual sensation or satisfaction."

Yang et al. (1998) concluded in their study into the innervation of the penile shaft and glans penis that: "The distinct pattern of innervation of the glans emphasizes the role of the glans as a sensory structure."

In a survey of men circumcised as adults for medical (93%) or elective (7%) reasons, reported that adult circumcision appears to result in worsened erectile function (99% confidence), decreased penile sensitivity (92% confidence), no change in sexual activity (88% confidence) and improved satisfaction (96% confidence). Of the men 50% reported benefits and 38% reported harm. Overall, 62% of men were satisfied with having been circumcised." Fink attributes the improved satisfication to the respondee's aesthetic considerations and to a resolution of previous painful conditions. Fink grouped decreased sensitivity with ejaculation taking longer than the men desired. Only one question relating to ejaculation time had a significant result; the question directly addressing sensitivity had no significant difference. There is conflicting evidence whether this should be seen as evidence of decreased sensitivity or simply of delayed ejaculation. A study by Paick et al failed to find a correlation between increased vibrational sensitivity and premature ejaculation. Other studies and several other groups they cited showed that ejaculation can be significantly delayed using a local anesthetic cream to numb the glans and penile shaft.

An examinination of 7 circumcised and 6 uncircumcised males found no difference in keratinization of the glans penis. Bleustein et al. (2003) tested the sensitivity of the glans penis, and found no difference between circumcised and uncircumcised men, confirming the earlier Masters and Johnson study. Bleustein later followed up with a larger study, with the same finding. These studies relied on laboratory tests of sensation thresholds to mechanical or thermal stimuli, rather than on subjective reports of sexual sensation.

Sorrells et al. (2007), in a study funded by NOCIRC, measured the fine-touch pressure thresholds of 91 circumcised and 68 uncircumcised, adult male volunteers, They reported "[the] glans of the uncircumcised men had significantly lower mean (sem) pressure thresholds than that of the circumcised men, at 0.161 (0.078) g (P = 0.040) when controlled for age, location of measurement, type of underwear worn, and ethnicity." Waskett and Morris, however, on the basis of the unadjusted data, stated "we find no significant differences [...], consistent with previous findings."

Payne et al. (2007), in a study of the glans and shaft sensitivity of twenty circumcised and twenty uncircumcised men, reported that "No differences in genital sensitivity were found between the uncircumcised and circumcised groups."

Foreskin sensitivity
Some recent researchers have asserted that the foreskin may be sexually responsive. Opponents of circumcision have cited these studies, which report on the sensitivity or innervation of the foreskin, claiming a sexual role based upon the presence of nerve-endings in the foreskin sensitive to light touch, stroking and fluttering sensations.

Circumcision removes the ridged band at the end of the foreskin. Taylor (1996) observed that the ridged band had more Meissner's corpuscles — a kind of nerve ending that is concentrated in areas of greatest sensitivity — than the areas of the foreskin with smooth mucus membranes. Taylor postulated that the ridged band is sexually sensitive and plays a role in normal sexual function. He also suggested that the gliding action, possible only when there was enough loose skin on the shaft of the penis, serves to stimulate the ridged band through contact with the corona of the glans penis during vaginal intercourse. This gliding action was also described by Lakshmanan, (1980).

Sorrells et al. (2007), in the study discussed above, measured fine-touch pressure thresholds of the penis, and concluded "The transitional region from the external to the internal prepuce is the most sensitive region of the uncircumcised penis and more sensitive than the most sensitive region of the circumcised penis. Circumcision ablates" (removes) "the most sensitive parts of the penis." According to Sorrells et al., the five penile areas most sensitive to fine-touch are located on the foreskin. This is disputed by Waskett and Morris, who argue that Sorrells' "[table] 2 shows this applies only to their position 3, the orifice rim of the prepuce." However, they stated that after they used the Bonferroni method to correct for multiple comparisons, "this significance disappeared."

Boyle et al. (2002) argued that circumcision and frenectomy remove tissues with "heightened erogenous sensitivity," stating "the genitally intact male has thousands of fine touch receptors and other highly erogenous nerve endings&mdash;many of which are lost to circumcision." They concluded, "Evidence has also started to accumulate that male circumcision may result in lifelong physical, sexual, and sometimes psychological harm as well."

Sexual effects
There have been several studies of the effect of circumcision on sexual function.


 * In a study by Korean researchers of 255 men circumcised after the age of 20 and 18 who were not circumcised, Kim and Pang reported that masturbatory pleasure decreased in 48% of the respondents and increased in 8%. Masturbatory difficulty increased in 63% but was easier in 37%. 20% reported that their sex life was worse after circumcision and 6% reported that it had improved. "There were no significant differences in sexual drive, erection, ejaculation, and ejaculation latency time between circumcised and uncircumcised men." Kim and Pang concluded, "There was a decrease in masturbatory pleasure and sexual enjoyment after circumcision, indicating that adult circumcision adversely affects sexual function in many men, possibly because of complications of the surgery and a loss of nerve endings."
 * In a British study of 150 men circumcised as adults for penile problems, Masood et al reported a slight reduction in erectile function scores, from 22.41 before to 21.13 afterwards (60% confidence). 69% noted less pain during intercourse (95% confidence). 38% reported improved penile sensation (99% confidence), 18% reported worse penile sensation, while the remainder (44%) reported no change. 61% reported satisfaction with the results, while 17% felt it made things worse, and 22% expressed neutral sentiments. 44% of the patients (p = 0.04) and 38% of the partners (p = 0.02) thought the penis appearance improved after circumcision. The authors of the study concluded that the satisfaction rate was a 'poor outcome,' given the pre-procedure penile disease state and recommended discussing with prospective patients the results of this study during the informed consent process.
 * In an American study of 123 men, found that medically necessitated circumcision resulted in worsened erectile function at the 99% confidence level, de-sensitization and/or delayed ejaculation at the 92% certainty level, but improved satisfaction at the 96% confidence interval. Half of the circumcised men reported benefits, while 38% reported harm. "Overall, 62% of men were satisfied with having been circumcised."
 * Shen questioned 95 patients before and after circumcision. Eighteen patients suffered from mild erectile dysfunction before circumcision, but 28 suffered from mild or moderate erectile dysfunction afterwards (P = 0.001). Adult circumcision appeared to have resulted in weakened erectile confidence in 33 cases (P = 0.04), difficult insertion in 41 cases (P = 0.03), prolonged intercourse in 31 cases (P = 0.04) and improved satisfaction in 34 cases (P = 0.04). Shen concluded that more importance should be attached to the effect of adult circumcision on erectile function.
 * In a study of 42 Turkish men circumcised for religious reasons, Senkul found no significant effect other than a 60% increase in time to ejaculation at the 98% statistical confidence level. Senkul suggested that delayed ejaculation may in fact be seen as a benefit.
 * A study of 15 American men found no post-circumcision difference in sex drive, erections, ejaculations, and overall satisfaction.
 * A study of 4456 Ugandan volunteers concluded that "[a]dult male circumcision does not adversely affect sexual satisfaction or clinically significant function in men."

Comparative studies

 * An analysis of a national U.S. survey by Laumann concludes that "circumcised men have a slightly lessened risk of experiencing sexual dysfunction, especially among older men; and that circumcised men displayed a greater rates of experience of various sexual practices," including oral sex, anal sex, and masturbation. For example, among whites the "estimated ratio of the odds of masturbating at least once a month for circumcised men was 1.76 that for uncircumcised men."  Dr. Laumann provides two explanations for the difference in sexual practices. "One is that uncircumcised men, a minority in this country, may feel a stigma that inhibits them. Another is that circumcision reduces sensitivity in the penis, leading circumcised men to try a range of sexual activities."
 * A multinational study by Waldinger et al found that circumcised men took on average 6.7 minutes to ejaculate, compared with 6.0 minutes for uncircumcised men. This difference was not statistically significant. The comparison excluded Turkey, which was significantly different from the other countries studied.

Female arousal
O'Hara and O'Hara argue that foreskin is a natural gliding stimulator of the vaginal walls during intercourse, increasing a woman's overall clitoral stimulation and helping her achieve orgasm more quickly and more often. Without the foreskin's gliding action, they suggest, it can be more difficult for a woman to achieve orgasm during intercourse. Bailey et al. report that there is a preference by women for the circumcised man, mentioning that circumcised men enter the woman more easily and cause fewer traumas.


 * Vaginal dryness and female arousal : A study by psychologists Bensley & Boyle (2003) reported that vaginal dryness can be a problem when the male partner is circumcised. Bensley et al. reported that the lack of a foreskin in the male partner produces symptoms similar to those of female arousal disorder. The authors hypothesized that the gliding action possibly involved intercourse with an uncircumcised partner might help prevent the loss of vaginal lubrication. They stated that the respondents were self-selected, and that larger sample sizes are needed . Boyle et al. state that self-selection is unreliable.


 * Female visual arousal : A study (1988) of randomly selected young mothers in Iowa, where most men are circumcised, found that 76% found the circumcised penis looked more exciting. Although 88% of the women surveyed had only had experiences with circumcised penises, a majority of the 24 women with dual experience also felt this way.

Summary of research findings
Notes:
 * 1) If stated, author's analysis is used. Otherwise, significance is considered to be p <= 0.05.
 * 2) c = circumcised; uc = uncircumcised.