Study published in the Journal of Urology, Volume 167, Issue 5, Pages 2113-2116 (May 2002).  The study's purpose was to determine the effect of the prepuce (foreskin) on sexual intercourse. The researchers examined sexual function outcomes in men who experienced sexual intercourse in the uncircumcised and circumcised states.

The study chose as subjects men who were circumcised for medical reasons. Only 7% of the men were circumcised as elective surgery. Even with such a large proportion of the subjects being circumcised for having problems with their foreskin, 38% reported that it was worse being circumcised.

This is yet another study that shows that there is a significant percentage of men who are dissatisfied with their circumcision. See Penile Sensitivity and Sexual Satisfaction after Circumcision: Are We Informing Men Correctly? for a similar study. Both studies used adult men with penis problems. The adult circumcision was performed to correct their condition, although a significant percentage of the men found their condition was either worse or the same.