In a mans scrotum, there are little tiny tubes or ducts that areconnected to the testicles. These little tubes are called "vasdeferens." Their job is to carry the sperm from the epididymis tothe penis. When a man has an ejaculation, the sperm rides along inthe seminal fluid or semen to make its exit out the tip of thepenis. When he has a vasectomy, the doctor makes a tiny incision inthe scrotum, reaches in and "snips" those vas deferens, thuscutting off the delivery of the sperm. Thereafter, when a manejaculates, only semen comes out- minus the sperm. So as they say,he "shoots blanks". No semen are present, therefore eggfertilization cannot take place and therefore no pregnancy. Thevasectomy is a very minor procedure, usually done in the doctorsoffice.