Owl I remind that there are parts of the world where even fathers see their daughters naked from the moment they are born. Some societies expect them to clean, care, swaddle them, up to proclaiming it as desired and reasonable parenting. Besides: What to do, if other caregivers are not available, anyway?
I assume nobody here objects to a father changing a baby daughter's diapers or something, but in many societies, nudity that is appropriate for a baby is not considered appropriate for a teenager. Therefore, I have no problem with the fact that girls want to have some privacy from their father once they are at an age where other males may desire their bodies.
That said, I find it appropriate to have the same reservations towards same-sex parents as well. I do not think it is our place to tell a girl (or boy for that matter) what sort of people she (he) should demand privacy from in what situation. Personally, as a boy I am as comfortable nude in front of my mother as I am with my father, always have been (overall comfort levels varied over time, but they never discriminated by whom) but I do not want either in the room when I am washing my lower body.
