I've worked with a lot of dogs and I've only seen a couple females lift their legs like males. It's always a funny site cuz most of the time the pee dribbles down their leg. lol Course, then you gotta clean it up but still. At the dog daycare I worked at, there was a very dominant Lab X who would always pee on top of every other dog's pee and half lift her leg.
Funny stuff.