Intended for healthcare professionals

Education And Debate

How does male circumcision protect against HIV infection?

BMJ 2000; 320 doi: (Published 10 June 2000) Cite this as: BMJ 2000;320:1592

Prepuce:Anatomy and Functions

Prepuce: Anatomy and Functions

Oh dear, I see as how Brian Morgan put words in my mouth when he said, "but
I do have to question one of Rio Cruz's points - about the perfection of the
human form and after millions of years of evolution that no part of it might
be redundant." I've searched and searched through my letter and have been
unable to find where I ever mentioned the "perfection of the human form,"
let alone the suggestion that "no part of it might be redundant." I was,
however, gratified that Mr. Morgan did not, for one moment, suggest that the
prepuce is redundant. This is in sharp contrast with most serial
circumcisers who insist, despite all evidence to the contrary, that the
human prepuce is a redundant, vestigial piece of flesh whose ablation only
enhances the male form.

For those seeking biological justification for their amputation fetish, the
following may not be of help:

The male prepuce is the primary covering for the glans and inner mucosal
lining. Just as with the clitoris and inner labia of women, these structures
are normally internal organs shielded by the foreskin from abrasion, drying,
and callusing, and keeping them uncontaminated by dirt. The foreskin
comprises approximately half of the smooth muscle sheath called the dartos
fascia; most of the erotogenic nerve endings on the penis, including the
densely innervated Ridged Bands; specialized epithelial Langerhans cells, an
immune system component; thousands of coiled fine-touch receptors, lymphatic
vessels, the loss of which interrupts the lymph flow within a part of the
body's immune system; the frenulum, a sensitive tethering structure on the
underside of the penis rich in erotogenic nerves; the pheromone producing
apocrine glands; 50% or more of the total penile skin, which when amputated,
radically desensitizes and immobilizes the remaining shaft skin.1

The sub-preputial moisture contains lytic material (lysozyme).2
Lee-Huang has documented the anti-HIV action of lysozyme in
vitro.3 The prepuce offers protection against genital warts. Men
with intact prepuces tend to get fewer genital warts.4 When they do get
genital warts they tend to form on the distal tip, the part least protected
by the foreskin.4 Since genital warts are caused by human
papiloma virus (HPV), there is evidence of protection against HPV. The
foreskin also offers an abundance of other immunological

The foreskin gives the penis the ability to "glide."5 If unfolded
and spread out flat, the adult foreskin measures 15 to 20 square inches, the
size of a postcard. All this specialized skin gives the natural penis the
anatomically unique ability to smoothly "glide" within itself - which allows
non-abrasive intercourse without drying out the vagina.5-7 It
also contains several feet of blood vessels, including the frenular
artery8 and portions of the dorsal artery, the loss of which
interrupts normal blood flow to the shaft and glans of the penis,
potentially reducing its growth and damaging its erectile function; an
estimated 240 feet of microscopic nerves including portions of the dorsal
nerve; and, perhaps most importantly, between 10,000 and 20,000 specialized
erotogenic nerve endings of numerous types, which can discern slight motion,
subtle changes in temperature, and fine gradations in texture.

Does all this sound like vestigial, superfluous tissue? But not to worry.
Circumcisers will ignore this and all other evidence that may dissuade them
from targeting their favorite organ to mutilate. Especially if it's attached
to an infant that can neither fight back nor give consent.


  1. Cold CJ, Taylor JR. The prepuce.
    BJU Int 1999;83 Suppl. 1:34-44.

  2. Prakash S, Raghuram R, Venkatesan, et al. Sub-preputial wetness -
    Its nature
    . Ann Nat Med Sci (India) 1982; 18(3): 109-112.

  3. Lee-Huang S, Huang PL, Sun Y, et al. Lysozyme and
    RNases as anti-HIV components in beta-core preparations of human chorionic
    . Proc Natl Acad Sci U S A 1999;96(6):2678-2681.

  4. Cook LS,Koutsky LA,Holmes KK. Clinical presentation
    of genital warts among circumcised and uncircumcised heterosexual men
    attending an urban STD clinic
    . Genitourin Med 1993;69:262-264.

  5. Fleiss P, Hodges F, Van Howe RS. Immunological
    functions of the human prepuce
    . Sex Trans Inf 1998;74:364-367.

  6. Warren J, Bigelow J. The case against
    . Br J Sex Med 1994; Sept/Oct: 6-8.

  7. O'Hara K, O'Hara J. The effect of male
    circumcision on the sexual enjoyment of the female partner
    . BJU
    1999;83 Suppl 1, 79-84.

  8. Persad R, Sharma S, McTavish J, et al. Clinical
    presentation and pathophysiology of meatal stenosis following
    . Br J Urol 1995; 75(1): 91-3.

Competing interests: No competing interests

20 June 2000
Rio Cruz
Former University Professor, retired