Boy or girl? That's the first question we ask about new babies, new puppies and newly-found fossils. Fossils? Yep. Experts can tell if an ancient Egyptian mummy or a prehistoric human was a boy or a girl just by looking at the skeleton. Here's how they do it. The human skeleton offers insight into a person's life: it will show the signs of disease, malnutrition, and injuries, as well as aging and sex. Experts can identify a skeleton's sex by looking at two key areas: the skull and the pelvis.

Male skulls tend to be larger than female skulls, with heavier bones and a larger braincase. On the face area, there are bigger brow ridges, thicker jawbones and cheekbones, and the chin is more square than a female's chin, which is generally more pointed.

On the other hand, well, not hand, there's the pelvis. The female pelvis is shaped like a wide, oval bowl with a large opening at the top and a slightly smaller opening at the bottom. If a female has had children, the pelvis will also show this. The male pelvis is more narrow generally, and the opening at the bottom is more heart-shaped than oval.

Experts also use this type of information during forensic investigations. While the eyes may be the window to the soul, the skeleton offers experts a view into a human life.