I can see everyone has their own opinions, but the reason I say this is there is cold hard evidence to support this theory, it's suddenly dawned on me, people have seen first hand, my nephew has had double jaw at 16. When he was a child he had a good broad face, healthy looking kid. At age 12 he complained of a bloked nose; I don't know why maybe allergies, he started breathing through his mouth and within a Matter of 6months had crowding and forward head posture followed by a narrow long face. I'm certain it caused it or maybe it was a matter of coincidence. I guess the most facial growth occurs around that age which may have exaggerated it. I've talked to a surgeon and ent before both saying that oral posture does play a role but I'm sure it's more of the cause of the adverse growth. If you have a child peg there nose And I can guarantee you will see gross change. Also whats quite interesting is industrial town residents have on average 4mm vertical maxillary excess according to western price. Someone should research on more of the cause but let's end it there