Well, you certainly don't need to jump into the insidious pronoun nonsense. All of you are still in the learning stage. He might be acting out as an escape from the pressure and mystery of manhood and puberty.
Let your wife take the lead on this as your son is obviously comfortable enough to talk to her. No need for you to disclose your proclivity to him.
You really don't need to make it any bigger than it truly is. If anything, it's a natural curiosity that he needs to explore and too much outside concern and involvement can be as detrimental as narrow minded ridicule.
And certainly DO NOT let his school get involved!
