Since it's been a few posts since I clarified, I'll post the reasons why I care, in order of importance:
1) I want him to learn in whatever manner is most effective and comfortable.
2) I don't want to perpetuate marketing myths as fact (if they are).
3) I want to be able to pass on the instruments that I've played and loved to my children (if possible).
Nothing I've read here has convinced me that a lefty needs to strum or fret with one hand or the other, especially considering that I know MANY accomplished musicians on other instruments who have told me that "handedness" is a crock of pewp when it comes to instruments that require both hands to do important jobs.
That being said, I am going to get two guitars (likely classical) strung left and right and see which he prefers. I'm always open to more data, but at this point, I'm leaning towards, "whichever way he is comfortable learning is fine."
-Mark