Menstruation
Regular discharge of blood and tissue from the inner lining of the uterus through the vagina
Are there people who are men who experience menstruation?
Menstruation can occur in any human being who has a uterus and vagina.  People who are born with a vagina may transition socially and/or medically to being male.  Someone with a vagina who has transitioned to being male is a man. 
What body organs are involved in menstruation? Do some men possess #1? 