Study co-author Ronald Gray of the Bloomberg School of Health at Johns Hopkins University in Baltimore said the randomized trial of nearly 4,500 males was undertaken because previous studies showed that circumcision -- now recommended as an efficient way to reduce HIV transmission -- showed conflicting results.

"Previous studies have been problematic and shown contradictory results," Gray said in a statement. "Studies focusing on men circumcised in adulthood were highly selective, because there were medical indications for surgery, circumcised infants can't provide before and after comparisons and in most studies sample sizes were small and follow-up was short."

The research team studied 4,456 sexually experienced Ugandan men ages15 to 49, who did not have HIV -- 2,210 were randomized to receive circumcision and 2,246 had circumcision delayed for 24 months.

The study, published in journal BJU International, found 98.6 percent of the circumcised men reported no problems compared with 99.4 percent of the control group, while 99.4 percent of the circumcised men reported no pain during intercourse compared with 98.8 percent of the control group.