Merge 2 accounts to battle.net?

Are both WoW accounts registered under the same name, Leatus? If so, you are indeed welcome to merge each with your B.net account. This merging will not affect you or your son's ability to play simultanously. (You can merge up to 8 WoW accounts in total.)

With that said, please note that only one Authenticator may be associated with a B.net account. So, should you and your soon each possess a separate Authenticator for your respective WoW accounts and find this separation more convenient, you may wish to hold off on that merge or elect to create one B.net account for you and one for your son.

Also of note:

http://us.battle.net/faq/index.html

Q u o t e:
Q: My family plays World of Warcraft together. Should we create a single Battle.net account for all of our World of Warcraft accounts?
A: No. Sharing access to a World of Warcraft account, other than by a parent or guardian with a single minor, is a violation of World of Warcraft’s Terms of Use. You should create a separate Battle.net account for each family member’s World of Warcraft account. In addition, future Battle.net features will make it beneficial for players to have the Battle.net account they use associated with their own online identity. Creating separate accounts for you and your family ensures you will be able to take advantage of these features when they are introduced later on.

Q u o t e:
What if 2 people log onto the same battle net account in diff. states and play with merge accounts. Is that ok to do?

Only two people may ever access an account, Xblaze. That would be one adult, registered to the account and one minor child, that the registered adult is the parent or legal guardian of. Though technically speaking as long as the people accessing the account are permitted to, it is alright to do.

Be warned though multiple locations will look suspicious so it is possible that the account would be temporary locked. You'd receive an e-mail allowing you to unlock the account so it is fairly easy to remedy.