In technical psychological jargon, koro is known as genital retraction syndrome. In layperson's terms, it's a pathological fear that the genitals are shrinking into the body. Many victims of koro believe that their genitals will be completely sucked into the body, causing death. While this condition occasionally occurs in women, it is much more common in men¹.

Koro is a considered a culture-bound syndrome, meaning that it only occurs in certain cultures, and does not directly correspond with diseases or conditions recognized by Western medicine. It is most common in China, Southeast Asia, and Malaysia, although outbreaks have occurred in Africa as well. The condition tends to have a different name in every region, but these names often translate as 'shrinking penis'².

Causes and Cures

Commonly cited causes of koro include witchcraft, sexual relations with prostitutes, masturbation, and food poisoning.

• In some parts of Africa, lynch mobs have attacked so-called penis snatchers based on accusations of men who claimed that the evildoers have somehow caused their genitalia to retract into the abdomen. Later medical examinations,
  however, showed the accusing men to be completely intact.
  
• In China, men may believe that the yin/yang balance of sexual relations is fatally disrupted when 'male essence' is released in any situation other than spousal intercourse.
  
• Mass hysteria has often caused widespread epidemics of koro, such as the one in 1967 purportedly caused by eating contaminated pork in Singapore. Public reassurance from doctors and the government was enough to quell the epidemic.
  

Ethnographic psychologists³ consider koro to be closely related to panic attacks precipitated by sexual anxiety. Attacks of koro are often set off when men are in situations that would normally cause the male genitals to shrink slightly, such as emotional distress or cold temperatures.

While there are no substantiated reports of the condition itself resulting in any physical damage to the individual, many sufferers have unfortunately inflicted harm upon themselves in frantic attempts to stretch the penis to prevent further shrinkage. It is not unusual for those with koro to resort to using mechanical devices such as clamps or weights⁴.