What causes blood in sperm?

It is not unusual for a man to notice blood in the semen, the fluid that carries sperm. Doctors call this hematospermia. There are several reasons why this might happen. But quite often, no specific reason is found.

Here are possible sources for blood in the semen:

• Prostate or bladder infection

• An enlarged prostate (benign prostatic hyperplasia or BPH)

• Surgical procedures such as a prostate biopsy or cystoscopy (bladder scope procedure)

• Trauma to the testicles or prostate, which might happen after horseback riding or riding a bicycle

• Very frequent masturbation