The incredible disappearing penis

Chances are you’ve never heard of koro. It’s a rather rare mental condition that involves the irrational fear that one’s external genitals are shrinking or retracting. Koro predominantly afflicts men, who literally worry that their penis is disappearing (in the much less common case of women, the supposedly shrinking body parts are the vulva and nipples).

The syndrome is most frequently encountered in southern China and elsewhere in Southeast Asia, notably Malaysia and Indonesia, where it has been known since ancient times and where a series of epidemic outbursts was reported throughout the 20th century, most recently in the mid 1980s. Koro is recognized as a sexual disease in traditional Chinese medicine.

While koro tends to be most prevalent among ethnically Chinese men, epidemics have also occurred among native inhabitants of India, Nepal and Thailand. Since the late 1990s, a series of well-reported small-scale outbreaks, frequently associated with rumours of witchcraft, have spread from West Africa to as far as Sudan and the DRC.

For individuals, episodes of koro typically involve a sudden onset of intense anxiety that can last for several hours to as long as two days. These episodes can be chronic and recurrent. Other than the fear of penile shrinkage, retraction and disappearance, symptoms include:

  • a perception that the shape and muscle tone of the penis is changing;
  • fear of sterility and loss of sexual power; and
  • fear of madness, spirit possession and impending death.

While medical examination has revealed no actual cases of penis shrinkage, koro sufferers have been known to try to allay their fears by “manual or mechanical penile traction” or “anchoring” their penis using string or some sort of clamping contraption. Ouch!

The ageing penis

Quite clearly koro is just an irrational phobia, but while there is no medical evidence for any man’s penis ever having disappeared other than by way of tragic accident or surgeon’s scalpel, your penis does most definitely undergo a number of changes as you grow older.

Moving from your sexual prime at around the age of 30 into middle and old age, some of the most noticeable changes include the following:

  • As their testosterone levels decrease naturally with age, men’s sexual function tends to decline as well, leading to lower sperm quality and volume as well as a decline in the speed, quality and maintenance of erections.
  • Weight gain common in older men can result in an apparent decrease in penis size as abdominal fat may partially “bury” the shaft of the penis.
  • Many men also experience a slight but noticeable actual decrease in the size of their erect penis as they get older, both in terms of length and girth. This may be the result of blockages in the penile arteries as well as a steady build-up of relatively inelastic collagen in the fibrous sheath that surrounds the erection chambers .
  • Weakened bladder muscles, frequently accompanied by an enlarged prostate gland, tend to result in a gradual decline in urinary function and a weakening urine stream.
  • A slow loss of pubic hair.
  • Reduced blood flow with age causes the head of the penis to gradually loose its purplish colour.
  • Testicles tend to shrink from around the age of 40.
  • The penis tends to become less sensitive and can become curved with age.

(Andreas Späth, Health24, March 2010)

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