Be aware that with US citizenship come responsibilities. Be sure that you consider all requirements once he is no longer a minor (age 18).
Also, you cannot benefit from his citizenship until he is 21, AND as the parent of a US citizen, it will be difficult to obtain a non-immigrant visa (such as tourist and business) to the US.
Depending on the circumstances, claiming citizenship if there is no immediate benefit may not be in your best interest. Once he has citizenship, you cannot renounce it for him; he must be of legal age. You need to consider all of the implications which is the reason for an attorney consultation.

