I do not really coach just help out at clubs/events sometimes. However I do not treat boys and girls differently as far as I am aware of. I try to assess the player on an individual basis and provide help in the areas they need help, I would not think that the player is a girl so I should teach her in a particular way.
It is interesting to think about coaching though for example at the weekend I helped out at a girls event, I told the players they were playing too fast - what did that mean to them - nothing. What I needed to do was work why they were playing too fast, were they considering all the possible moves they could make, were they evaluating the position - i.e. what were they not doing that they should be doing, that was making them play too fast. I was not thinking are they a girl or a boy.
It is my belief that girls and boys as a whole do vary in the way they play chess and even in the way they respond to coaching, but on an individual basis the overlap is quite large and any individual will exhibit a mix of characteristics.