It's tricky business, but there's a lot you can figure out from a human skeleton if you know what you're doing.
In mammals, the sex of a baby is determined by the chromosomes it inherits from its parents. But, the combination an animal inherits can be quite different.
Sure, there are physical differences but outside of mammals, the terms "male" and "female" take on different meanings.
What are the odds of giving birth to a boy? Learn more on this Moment of Science.