Were We Wrong About Circumcision? A Closer Look at the Anatomy and Evidence

The host says the earlier video on the pros and cons of circumcision drew varied responses, including some fair criticisms. Some viewers questioned whether circumcision actually reduces sexual pleasure. Others asked for more detail about the anatomy of the foreskin and what it actually does, and some challenged the scientific research used in the original video.

The host adds that another major question went beyond the science: whether parents should be making this decision for their children. The video says it will answer the anatomical and scientific questions, take another look at the research, and clear up some misconceptions, while acknowledging that it will likely be controversial again.

The host explains that the foreskin, also known as the prepuce, is a double-layered fold of tissue that normally covers some or all of the glans penis, the tip of the penis. It is not simply an extra piece of skin: it contains blood vessels, connective tissue, smooth muscle fibers and sensory nerve endings.

Its functions include protecting the glans from friction and irritation while keeping the area relatively moist. The host also describes a gliding mechanism. Because the foreskin is a mobile fold, it can move back and forth along the shaft during sexual activity, reducing friction and changing how mechanical forces are distributed. Circumcision removes some of this mobile tissue, which can change the amount of movement possible.

On lubrication, the host says that although the foreskin helps maintain moisture and reduces friction through gliding, it does not produce large amounts of lubricating fluid. The protective and mechanical functions are real, but the role of the foreskin in lubrication is often exaggerated.

The host notes that some people cite the claim that the foreskin contains approximately 20,000 nerve endings, and that removing it therefore removes a large amount of sensory tissue. The host says this number has not been established by reliable anatomical research.

This does not mean the foreskin is insensitive. The host says it does contain different types of sensory nerve endings, including specialized receptors involved in detecting light touch, and that certain regions, particularly the frenulum on the underside of the penis, can be especially sensitive to stimulation.

The host argues that sexual pleasure involves much more than peripheral sensation or the number of nerve endings a structure has. It also involves how the spinal cord and brain process sensory information. The host also points out that sexual function, sexual satisfaction and sexual sensitivity are not necessarily the same thing.

Sexual function includes achieving an erection, ejaculation and orgasm. Sexual satisfaction refers to a person's overall experience of sexual activity. Sexual sensitivity, in this context, refers to how effectively different areas of the penis detect stimulation. These are related but not completely interchangeable, and someone could experience changes in sensitivity without developing erectile dysfunction or losing the ability to climax.

The host notes that this distinction matters for interpreting research, because some studies look at erectile function, orgasm or overall satisfaction, while others examine how sensitive different parts of the penis are to physical stimulation.

The host describes a claim raised by several viewers: that circumcision not only removes sensitive tissue but may also cause the exposed glans to become less sensitive over time, because it is no longer protected by the foreskin. Some versions of the claim go further, suggesting the glans becomes progressively more keratinized, almost like developing a callus, which would further reduce sensitivity.

The host explains that keratinization is a normal process involving keratin, a structural protein that helps protect epithelial tissues. The real question is whether circumcision actually makes the surface of the glans thicker or more keratinized, and whether any such change would reduce sensitivity.

The host cites a small study published in the British Medical Journal in 2000 that examined tissue from the glans of circumcised and uncircumcised men. The study found similar degrees of keratinization between the two groups.

The host cautions that this does not necessarily mean circumcision has no effect on the surface of the glans. The study was small and research on this particular question is fairly limited. Still, the claim that circumcision inevitably causes the glans to develop a thick, calloused surface is not well established by the available evidence. The host adds that even if keratinization differed, it would still need to be shown that those differences translate into reduced sexual sensitivity.

The host points out that a man circumcised as an infant cannot personally compare sexual sensation with and without a foreskin. Men circumcised as adults, however, experienced sexual activity both with and without a foreskin, and there have been fairly large studies of such men.

The host says these studies generally did not find a significant decline in overall sexual function or satisfaction following circumcision. Some men reported improvements in sensitivity or overall experience, others reported little change, and some did report decreased sensitivity or less satisfying experiences. The host's takeaway is that both circumcised and uncircumcised individuals can have normal and satisfying sexual function.

The host recalls that the earlier video said circumcised individuals are less likely to get urinary tract infections, phimosis and HIV, meaning circumcision was associated with a reduced risk of these conditions. The host says some viewers questioned these studies, especially the ones on HIV, and admits the earlier video may not have made clear that the reductions in absolute risk were small.

The host explains that a study might report a 50 to 60 percent relative reduction in HIV risk from circumcision, which could suggest that circumcised people are far less likely to get HIV. However, relative risk and absolute risk are not the same thing.

As a hypothetical, the host describes a study finding that the risk of HIV in a particular population fell from 2% to 1%. That would be a 50% relative reduction but only a one percentage point absolute reduction. The host says this does not mean the reduction is unimportant, especially in populations where HIV is relatively common, but the actual benefit depends on a person's underlying risk. The strongest evidence comes from studies of heterosexual HIV transmission from women to men in certain higher-risk settings, and the host stresses that safe sex practices remain the most important way to reduce HIV risk.

The host says circumcision has been associated with a lower risk of UTIs in infant boys. However, most healthy infant boys do not develop a UTI in the first place. Even though circumcision can reduce the relative risk, the absolute benefit for most boys is fairly small.

The host defines phimosis as a condition in which the foreskin cannot be retracted behind the glans, and notes that removing the foreskin eliminates the possibility of developing phimosis later. The host stresses that this does not mean uncircumcised boys will develop problems, since most do not.

The host says a non-retractable foreskin is completely normal in infant and young boys and usually requires no treatment. Even when symptomatic phimosis develops, circumcision is not necessarily the only option: topical corticosteroids and gentle stretching can often be effective, and there are surgical procedures that preserve the foreskin. The host acknowledges there have still been cases in which circumcision was necessary.

The host concludes that circumcision does have some legitimate medical benefits, but for most healthy individuals the actual reduction in risk of developing these conditions is pretty small. Even when a medical problem does develop, the host says circumcision is not always necessary to treat it.

The host says that, unlike the earlier scientific discussion, this part moves into the ethical, religious and cultural aspects of circumcision, and that the host will not share a personal opinion. The host summarizes arguments from both sides.

Those who support parental choice point out that parents make medical decisions for their children all the time, including decisions with potential risks, benefits and lifelong consequences or trade-offs, and that for some families circumcision has significant religious or cultural importance. Others argue there is an important difference between treating a medical condition and performing an elective procedure on an otherwise healthy child. Because circumcision permanently removes normal anatomical tissue, some believe the decision should be left to the individual when old enough to make it.

The host notes that two people can look at the same medical evidence and reach very different conclusions. Science can describe the anatomy, potential benefits and risks of circumcision, but it cannot determine how much weight parental decisions, religious beliefs or an individual's right to decide about their own body should receive.