Male menstruation is a term used colloquially for a type of bleeding in the urine or faeces, reported in some tropical countries. It is actually caused by parasite infestation of the urinary tract or intestines by Schistosoma haematobium, and cases of it are actually schistosomiasis, formerly known as bilharziasis. In some tropical peoples that work in wet places such as rice fields, most boys pick up Schistosoma, and start the bleeding, about puberty when they start working in the rice fields, and uneducated locals think that it is normal and refer to it as the male equivalent of female menstruation, and call it by their native language word for "menstruation".
In at least one case, it was reported that a boy in an affected area started work in a factory instead of the rice fields, and so did not pick up Schistosoma, and did not develop the bleeding, and his father took him to a doctor asking for investigation of primary amenorrhoea.
In some cases of this affliction, the condition is unnoticeable until after a slight shrinkage of the penis. This event is not common amongst all males, but it can be harmful if signs are not noticed and treated. Males between the ages of 13 and 21 are recommended to visit a doctor at least twice a year to ensure there are no possible signs. Some signs, which do not always happen, are a yellowish discharge from the penis, excitedness when least expected, and an odd feeling which many with this condition call undescribable.
This is to be distinguished from genuine menstruation in: