Hematospermia is the term used for blood in the seminal fluid. Semen originates from the testicles, epididymis, vas deferens, seminal vesicles, and prostate, with the majority coming from the seminal vesicles and the prostate. Most cases of hematospermia is caused by inflammation of the seminal vesicles, and will usually go away on its own. Other causes of hematospermia include STDs ( Chlamydia ) or a tear or inflammation of the prostate. (Other symptoms of prostatitis include urinary frequency, and discomfort in the lower abdomen).