From Wikipedia:
Urology is the branch of medicine that focuses on the urinary tracts of males and females, and on the reproductive system of males.
Andrology (from Greek: ἀνδρο, andro, "man"; and λόγος, logos, "knowledge") is the medical specialty that deals with male health, particularly relating to the problems of the male reproductive system and urological problems that are unique to men.
So depending on what you have going on, either specialist would be appropriate.
Morgannon
I believe they're called "Urologists."