It is supposed to reference that Ghetis is N's father. In the Japanese version the sentence translates to something like "son of mine", or something like that...
Well, this is rather signifigant. The only other person to have a last name as a character in a Pokemon game was Blake Hall in the second Pokemon Ranger game.
@Sean
While I'm happy for your discovery, this is actually old news (Harmonia isn't even changed from the Japanese name). We've more or less known Ghetsis was N's father. Spelling it out even further with "N Harmonia. Ghetsis Harmonia." just earns a Captain Obvious award.