From my understanding (and I'm nowhere near an expert on this), genderqueer is not identifying as either male or female. Gender is more than anatomy, it's also what you identify as and believe yourself to be. For example, young children know they are male/female before they really know the physical differences between the two.

Basically, genderqueer is not identifying as the biological/physical gender you are born as, but not necessarily identifying as the other gender or labeling yourself transgender. Think of gender as a spectrum if that helps. Just like sexuality ranges from gay to straight with varying levels of bisexuality, gender works the same way.