Aspergers Syndrome perhaps? Not to jump to conclusions, but children and adults with Aspergers tend to exhibit such socially unacceptable behavior such as relieving themselves in the most strangest of places because in their minds, they just don't register that it's socially unacceptable. Trying to discipline them will only agitate them and cause them to continue such behavior out of spite.
Thank you very much for getting back to me. I have already set him up with an appointment with a behaviorial specialist to try to get to the underlying causes. Thank you again for your prompt insight.
He probably does not know why he behaves in this fashion. As adults, we often expect that children are aware of the 'motives' underlying their behavior, but they often have no such awareness. Set a firm limit on the behavior - i.e., urinating is to occur in the bathroom and nowhere else. Let him know there will be a consequence (e.g., loss of computer or video games for a 24-hour period) if there is any recurrence. If there is, seek an evaluation with a mental health clinicvian.