| | Re: How many people do you have in your family?
I agree that have sounds odd but I don't think the reason is power - or not quite in the way you suggest : I have a brother and a sister / I have a lot of relatives /I have several friends in Australia - no assumption of power there.
For me the problem lies with "in your family". If I say Do you have friends in the States? or Do you have a pen in your bag? it implies that you are outside Australia or the bag - not a component of it..
But with the family it's different. You are in the family too - you're part of it. And one component can't have something which is another equal component of the whole. This explains too why the student can't say I have 32 students in my class but the T can. The S is part of the class, whereas the T is not - s/he's outside the group.