So, a fascinating paper just came out in nature detailing a technique for identifying sex-specific characteristics in non-avian dinosaurs (specifically, Medullary Bone which is involved in egg shell development), and applying it to identify the sex of a T. rex specimen. This is great because (1) establishing sex from fossil is notoriously difficult; (2) it's a really nice example of using a combination of phylogenetic studies, molecular analysis, and other techniques to uncover tricky things about the past. That tissue is typically present around when birds are laying eggs. Still, why say they've discovered a pregnant t. rex? *sigh*