in my dreams, gender usually never comes up, only when it seems important to the proceedings. I had one not too long ago where I was male, and I only knew that because me being male was important to what was going on. I was at my dad and stepmom's, where this new girl was living. She wasn't related to me in any way, and we were kind of hitting it off, and we were going to hook up in her room after everyone went to sleep. Things go wrong, however, and I end up hiding in her closet, meanwhile, i'm reading her diary, where she calls herself Daria. At this point, the symbolism seems obvious. A male me was hiding in a symbolic female me's closet from the people in my life least likely to accept me as a transgender female.
That's the only time gender comes up or seems important, though, is when it actually contributes to the dream itself.