They never bothered to count the ribs?
Normally they can identify a female skeleton by the spacing in the pelvic bones, and the brow of the skull, along with other features on the skull. The problem is that not all burials are intact, and the only way you can be absolutely sure, is to do DNA testing if at all possible. It fascinates me that they can now even tell where a person most likely came from, and what their diet was. It's also amazing how they can recreate the image of a person by placing muscle and tissue onto a skull that has been recreated by laser scanning the original...even when not all of it is there.