Root of Allergies: 5 Most Incredible Discoveries of the Week Including a group of dancing dinosaurs. By Newser Editors, Newser Staff Posted Jan 9, 2016 5:05 AM CST 0 comments Comments Blame him for that hay fever. (Shutterstock) (Newser) – The revelation that childbirth is harder than anyone thought and a giant blue sapphire make the list: MRIs Reveal Hidden Tolls of Childbirth: Childbirth can take a toll on a woman's body that rivals the damage endured by hardcore athletes—and researchers have the MRI scans to prove it. A University of Michigan team found that 15% of women suffer pelvic injuries that don't heal, and one commonly prescribed exercise won't help. Sex With Neanderthals May Explain Modern Allergies: Two studies suggest we can blame our allergies on Neanderthals. Scientists note that Neanderthals and a second now-extinct hominid were living in Europe and Asia for hundreds of thousands of years before humans arrived. When we started interbreeding with them, we took on some of those early genes. That's where the catch comes in. We've Pushed the Earth Into a New Geological Age: Researchers say the case for a new "Age of Man" geologic time period—the Anthropocene era—is stronger than ever, based on permanently etched markers such as radioactive fallout and materials like concrete. Exactly when the new era began is still being debated, but a nuclear milestone might be key. Biggest Blue Star Sapphire Is Found: Gemologists in Sri Lanka say they've dug up the largest blue star sapphire ever found at a mine in Ratnapura, known as the City of Gems. It weighs in a whopping 1404.49 carats and has lots of zeroes in its estimated worth. Awesome Dinosaur Discovery: They Danced: It must have been an amazing sight: Paleontologists now say that dinosaurs danced—with gusto. More specifically, they think that some male dinosaurs did so as part of a mating display to woo females. A key insight came from observing modern birds. Click to read about more discoveries.