What does it mean when you have blood in your semen

Usually not serious: Blood in the semen by itself without any other symptoms is not usually a harbinger of bad things. Of course all men are afraid of prostate cancer, std's or infection. Many urologists will place patients emprically on antbiotics but usually th blood disappears with time.

Trauma / infection: it means you either have some type of trauma or an infection - need to see a doctor

Here are some ...: Seeing variable degree of blood in semen is nothing unusual, but has annoyed and even terrified many men as well as have baffled many professionals. Fortunately, the accumulated experience of more 5 decades has proved there has been usually nothing serious at all. This is caused by rupturing small vessels of seminal vesicles or ejaculatory ducts by unknown causes during vigorous contraction for...