The effect of male circumcision on sexuality - Kim - 2006

Found via Mensactivism.org, another study about circumcision:

In South Korea, many men are circumcised as adults, after they have led active sex lives; these men can compare their sex lives before and after circumcision. This is because circumcision in South Korea is a relatively recent event, having reached >100% circumcision rate (compared with the male birth population) in the last 20 years. This unique situation, in terms of research on circumcision’s effect on sexuality, contrasts with other cultures where adult circumcision is rare, simply because circumcision is practised on neonates or pre-teens. Even when such men have been found and interviewed, they do not represent the general population, but those with medical indications or religious convictions about circumcision. In this sense, South Korea provides a unique opportunity to study the effect of circumcision on sexual activity in a truly general population.

[...]The effect of circumcision on masturbation is interesting, as preventing masturbation was one of the main original reasons often cited for the popularity of circumcision in America. The frequency of masturbation seems to have decreased only slightly after circumcision, but there was a striking difference in the pleasure of masturbation, with 48% reporting less pleasure from masturbation after circumcision, in contrast to 8% who reported more pleasure. We think that this is one of the most important findings of the present study. This is consistent with more men finding masturbation more difficult after circumcision, possibly because of the loss of the foreskin.

Of the 138 men aged >30 years who could compare their sex lives before and after circumcision, >70% (102) reported that there was no difference. However, circumcised men were more than three times more likely to report less enjoyable sex lives after circumcision than better sex lives (28 vs eight men). While decreased sensation was the most frequently cited reason (21 of 28 men) for a less enjoyable sex life, complaints about the physical effects of circumcision on their penises and consequent adverse effects on sex life were also prominent (13 of 28; multiple complaints were separately counted). While this is consistent with our earlier study, it suggests that more attention should be given to anatomical alteration of the male genitalia by circumcision. This conclusion is supported by the reports of major scars by ≈ 9% of the circumcised men in the present study.

In summary, we studied the effects of circumcision on sexuality. There were no differences in sexual drive, erection and ejaculation, but circumcised men reported decreased masturbatory pleasure and sexual enjoyment. We conclude that adult circumcision adversely affects sexual function in a significant number of men, possibly because of loss of nerve endings. In addition, ≈ 9% of the circumcised men reported severe scarring of their penises, and this population probably overlaps with those who reported insufficient skin resulting in uncomfortable erections, penile curvature from uneven skin loss, and pain and bleeding upon erection/manipulation.