They're not going to establish dominance for quite a while. Eventually, my guess is that the girl will get what she wants (as it should be

) In the meantime it will probably be situational, assuming they're essentially the same personality type. If one's very laid back it will sort out quick. If both are very pushy, they'll butt heads more. But in a male/female pair it's not likely to be that big a deal, especially if they don't live together and aren't competing full time for toys.
I'd let them play as hard as they want to, provided they both keep coming back for more. At least until your nerves are shot -- then break it up just to have some peace and quiet
Seriously -- they will wrestle and growl and make the most godawful noises. If you interrupt by making a sound across the room and they stop, then BOTH go back immediately to playing, they're fine. If one is desperately trying to get away from the other, break it up.
But at this age they're like little pirates going "Arrrrrrr!" at full voice. Let them use up the energy. Think of them as toddlers running around screaming and rolling around in the yard. Frightening behavior in an adult, good fun in a child. Tired puppies are goooood puppies, and nothing tires them out quicker than wrestling with a fellow puppy!
When one lets out a cry of pain, watch the other's reaction. The other pup should immediately stop and back up. As long as that's happening, they're respecting each other and keeping the play within fair grounds. Biting, to little puppies, is fair game. If they're not crying about it, don't be concerned. Obviously if they're running into furniture or endangering themselves near stairs, etc., you need to step in and keep them safe.
But this is a very important developmental period for learning just how far to push somebody else. Getting that cry of pain and respecting it is crucial. If you always break them up before they reach that point, THAT, as you said, will lead to problems down the line, because they won't know or respect their own strength.