I believe I learned this in my forensics class. The skeleton of an (older) female is usually determined by the pelvic region. The wide hips and cervix area. (As women grow their hips and cervix move outward in order to give birth and house a child) In adolescent skeletons the hips and cervix on the female haven’t moved outward yet. Therefore making both the male and female skeletons look almost identical in the region they most use to determine (the pelvic and hips) I hope that’s right and what you were lookin for!