Hey dr I have a question...What could be the issue when a man sees blood sperm?

Hematospermia. May be coming from seminal vesicles, prostate, spermatic cord likely benign but there is some % from cancers. Discuss with urologist.
Hematospermia=common. Some bleeding in the seminal vesicles (glands in the prostate) is quite common, usually painless, and is often of not much concern--but disturbing to see. Infection, urethral stricture, trauma (prostate biopsy), bleeding disorder etc..Can cause bleeding and thus blood in sperm. If recurring or having pain or any other symptoms, i advise seeing doc for eval. Good luck.