I agree with you Girl : jaws developpement is also determined by genetical factors.
I was talking with Kavan about genetic alteration of the whole humanity,
Of course, there are individual variations, transmitted from generation of generation.
My sisters' jaws are kind of narrow as mine.
But regarding my class 2 issue, it's defietely my bad oral habits that lead to that. But I saw that oral habits can also be genetically determined ! A family of thumb suckers exists, it can be a neurological habit, genetetically determined !
It's not always evident to distinguish between the factors.
For example, my partner is a mouth breather (with long face syndrome and a huge sleep apnea.)
Is it because he had already a narrow airway when he was a child that he was forced to breath with his mouth ?
Or it is the habit of breathing with his mouth that left him with a narrow airway (his jaw grew vertically and not forward) ?
I believe it's a vicious circle.
Anyway, the best thing to do is to have a consultation with an HONEST orthodontist before 8 to expand the jaws. There are not orthothropics practicionner everywhere and orthodontists don't always do harmfull stuff.
The things to avoid is :
headgear (because it involved the TMJ and moved the upper jaws backward => flat cheeks)
retractive braces (new kind of braces exist that doesn't retract the jaws)
extractions (however, I read that it can be necessary but very seldom and has to be avoid as much as possible).
The dentist's book I've read mentionned Mike Mew only one time :
She was talking about that orthodontists doesn't care about the aesthetical damages of braces etc. contrary to Mew who is aware of that issue.