Try this exercise: Find a 3×5 index card. One side, 15 square inches, equals the average surface area of a man's foreskin — about half of the total surface area of his penis.

Now fold the card in half lengthwise and bring the two short ends together to form a cylinder. The outside of the cylinder represents the external foreskin, a more sensitized, retractable extension of the skin on the penile shaft. The inside represents the delicate, lubricating mucosal lining that sheathes the glans, or head, of the penis.

These outside and inside folds are comparable to the external and internal aspects of the foreskin's closest anatomical analog, the eyelid. And, like the eyelid, the foreskin bristles with nerve endings: about 36% of the total penile allotment.

With this simple overview, you probably already know more about the foreskin than your doctor does. What most American health professionals are taught about it is even more succinct: It's the part of the male anatomy removed in a circumcision.

Despite its highly articulated, specialized physiology, the foreskin is commonly considered as disposable as the paper version you've just created. Every year the foreskins of an estimated 1 million U.S. infants end up in the trash.

Medical arguments for circumcision have always centered on hygiene and prophylaxis. Victorian-era authorities associated carnality with a wide range of mental and physical disorders; the pain of unanesthetized circumcision (for infants of both sexes) was deemed salutary "aversion therapy" against masturbation.

Morals shifted, but the foreskin became implicated in a new set of perils: renal cancer; urinary tract infections; cervical cancer in the female partners of uncircumcised men.

Today the main argument against the foreskin is its supposed correlation to sexually transmitted disease, especially AIDS. And especially AIDS in Africa.

With American funding, thousands of adult African males have recently undergone circumcision to study their subsequent HIV infection rates compared with those of uncircumcised counterparts. HIV infection rates among uncircumcised control groups (often before studies had run their course) led researchers to conclude that the foreskin significantly contributes to seroconversion.

There is ample cause to question this conclusion.

First, a hard reckoning: Several African countries with some of the highest rates of HIV/AIDS in the world (Nigeria, Ethiopia, the Ivory Coast, Gabon) already circumcise at rates exceeding that of the United States.

Moreover, efforts to export American genital norms expose a glaring hypocrisy: The United States has both the highest HIV infection rate and the highest circumcision rate of any industrialized nation. By comparison, Australia, New Zealand and the Netherlands could take a more plausible "intactivist" stance. Their predominantly uncircumcised men have some of the world's lowest HIV infection rates.

Many developing countries, such as India, Thailand and Brazil, have successfully combated AIDS not through circumcision but through aggressive health- and condom-education programs. While hardly rid of HIV, these nations have dodged the devastating mortality rates of, say, Uganda or Botswana.

Surely there is as much to learn from intact Dutch and Thai men as there is from circumcised Ugandan men, but American medical/cultural bias has preempted this line of scientific inquiry. Indeed, the zeal to circumcise has eclipsed the study of whole categories of prophylaxis that may be as effective as circumcision-or even more so. Some of the most promising HIV preventives in development are microbicides administered topically—to the very type of mucosal tissue that circumcision destroys.

How circumcision bears on long-established safer sex guidelines is uncertain, but consider the basics: The procedure slices off more than one third of the penis' nerve endings, toughens the unnaturally exposed glans and negates built-in lubrication and stimulation. Is it logical to expect enthusiasm among circumcised men for further— desensitizing latex barriers?

No one is promoting circumcision as a license for unprotected sex, but inevitably, in Africa and elsewhere, circumcision will be used not in concert with condoms but instead of condoms, potentially wiping out more than two decades' worth of safer-sex intervention. Also, in an environment where "cut" = "clean," women, who already constitute the majority of AIDS deaths in Africa, will have far less bargaining power to insist on safer sex with circumcised partners, and may seroconvert in even greater numbers.

Ironically, all arguments for prophylactic circumcision as a successful harm-reduction strategy may be built on a fundamental diagnostic flaw. Existing scientific data demonstrate that adult circumcision typically causes a marked overall decrease in sexual pleasure and erectile function. Statistics citing circumcision's efficacy against HIV may not reflect the foreskin's contribution to infection so much as demonstrate its contribution to sexual performance—and the potential risks therein. (Chalk one up for the Victorians.)

Confronted with complex, real-world dynamics, the limited scope of circumcision research may not help to stem HIV infection rates at all, but may actually sustain or even accelerate them. The president of Uganda and the Brazilian secretary of health have already reached this conclusion, denouncing recommendations for adult circumcision in their respective countries.

Even American public health officials admit that the arguments for circumcision are, at best, debatable. Still, proponents believe that they are doing something to counter AIDS. Bucking America's frustratingly puritanical aversion to condom-based HIV education, they may even feel comparatively progressive for taking a pro-circumcision stance. Nonetheless, most, if not all, of these proponents don't know what they themselves are missing, cannot understand what is lost to circumcision, and cannot appreciate how this loss may compromise other HIV prevention strategies. For them, the procedure is quick, easy, cheap—a potentially major impact derived from minor surgery.

But how minor, exactly? Look again at your index card, and imagine that amount of tissue being cut from anywhere on your body.

Minor surgery, so the quip goes, is surgery performed on somebody else.

From POZ, July/August 2007. Reprinted with permission. Copyright 2007 CDM Publishing, L.L.C.