Controversial new research casts doubt on the long-held belief that circumcision reduces sexual sensitivity for men who have undergone the procedure.
Circumcision, a procedure performed throughout history — for reasons ranging from the fulfillment of a biblical covenant to a means of curbing masturbation — has received both praise by those who tout its supposed medical benefits and scorn from those who claim it has traumatic aftereffects.
Now, in a Canadian study appearing in the most recent issue of the Journal of Sexual Medicine, researchers found that the glans, or head of the penis, is just as sensitive on a circumcised man as on an uncircumcised one.
"It's probably the best study I've seen of this kind of work," said June Reinisch, the former director of the Kinsey Institute. Reinisch was not involved with the study.
Reinisch praised the study for using the best available technology, for matching circumcised and uncircumcised subjects on a number of important factors and for taking measurements where subjects were in an aroused state — something not done in previous studies.
"It's the state in which we're all interested," said Reinisch. "We're not interested in how [men] feel when they hold themselves when they pee."
Still, the benefits of circumcision remain controversial. Research in recent years has suggested circumcision might benefit men by lowering their risk for AIDS and other STDs. Other studies suggest that the procedure may limit the risk of passing the cancer-causing human papilloma virus (HPV) onto female partners, although the merit of those studies has been disputed.
The American Academy of Pediatrics reflects that doubt in its official policy, which states: "Existing scientific evidence demonstrates potential medical benefits of newborn male circumcision; however, these data are not sufficient to recommend routine neonatal circumcision."
In order to test the sensitivity of the penis, researchers had men disrobe and watch an erotic film. Cameras were used to measure the men's arousal.
Once aroused, researchers pressed increasingly firmer filaments against the erect penises until the subjects indicated they felt the touch, and then at the point where they felt pain.
In addition to comparable sensitivity between circumcised and uncircumcised men, the study also showed that the penis becomes less sensitive when aroused.
"When God invented sexual activity, the arousal response is actually a form of anesthesia," said Irwin Goldstein, editor of the Journal of Sexual Medicine.
"It actually makes more sense when you think of it that way," he said, explaining that if the penis became more sensitive, it might limit sexual activity and, therefore, reproduction.
While psychologist Kimberley Payne, one of the study's authors, said the research seems to refute the idea that the foreskin keeps the penis sensitive, she was hesitant to draw a broader conclusion from her study.
"This just scratched the surface, and there is so much more to look at," she said.
She said ultimately she hoped someone would be able to measure the full range of sexual sensation in circumcised and uncircumcised men during sex, but was unsure how that would be done.
Because her study only looked at two locations on the penis, Payne said future research would likely look at more areas and utilize more subjects.
Anti-circumcision groups were quick to criticize Payne's study.
The International Coalition for Genital Integrity released a statement saying, "Poor research investigating the sensitivity of the intact [not circumcised] and circumcised penis does not serve men."
ICGI director Dan Bollinger, who in the past has called circumcision "parental-elected penile reduction surgery," pointed out that the researchers did not measure the sensitivity of the foreskin, which previous research had said was the most sensitive area.
"All of us in the movement are rather surprised that this even got published," he said.
He points to a recent study published in the British Journal of Urology, which showed uncircumcised men had four times more sensitivity, as a better measure.
Dr. Robert Van Howe, a pediatrician at Marquette General Hospital in Michigan and one of the author's of the urology journal's study, said that the findings in his study had more relevance because of the larger number of patients involved and the greater number of areas on the penis measured.
He urges parents not to circumcise their children, but to allow the children to make that decision when they reach age 18. At that point, he said, only three out of every 1,000 males elect to be circumcised.
But both Payne and Reinisch criticized the Van Howe's study, which was funded by the anti-circumcision group the National Organization of Circumcision Information Research Centers, as biased.
"Scientific study must be conducted dispassionately and without bias. The motivation of this group is highly suspect," said Payne.
Van Howe rejected the notion of bias in his study.
"The study was based on an objective finding," he said. "There's no way you can change what a person felt or didn't feel."
But Reinisch said researchers could very easily have affected data because it was apparent to researchers which men were circumcised and which were not. She also pointed to the fact that men in the Van Howe's study were not aroused at the time of measurement as a possible source for the difference.
As for the failure to measure the foreskin's sensitivity, Reinisch said that was irrelevant, as it rolls back from the glans during arousal.
"The foreskin's job is to cover the penis and protect it," she said. "Its job is not to be a part of the sensitivity."
"Of course nerve endings are lost," she said of circumcision. "The question is: Does it make any difference in satisfaction? In pleasure?"
In the end, Reinisch said, circumcision will not affect a man's ability to be aroused or experience sexual pleasure.
"Nature has certainly provided an enormous amount of sexually sensitive tissue," she said, calling the brain the most powerful sex organ of all.
"I'm not suggesting everyone be circumcised," said Reinisch. "I'm suggesting that there are some benefits. … I believe it's really a personal choice."
Payne, meanwhile, said that she personally is opposed to circumcision, calling it "a barbaric practice."
"I sympathize with the efforts of [the National Organization of Circumcision Information Research Centers]," she said. "I would have loved to find evidence in my study to dispel the practice, but I did not and must report the findings accordingly."
"I hope that we will one day be able to establish … some sexual drawbacks to this procedure, but these studies do not."