Do sebaceous glands on penis become a problem, or are they just there for no reason?

Perhaps?: Sebaceous glands are present to provide oil to the skin. They are there because that is the way we are made. Occasionally we can have the plug up & cause a cyst to form. It is best to leave these alone. An skin/soft tissue infection in the genital area can be very serious. They may be unsightly but they are sterile. If you prefer removal, see a urologist, dermatologist or surgeon & b careful!