You can’t just ask politely
“Can we really tell male and female dinosaurs apart?” The answer is … probably not. That’s because the soft tissues that make up the sex differences don’t fossilize, and the differences in bone structure are minimal. Even with modern equivalents — gharials, a giant crocodile — it’s often difficult.
“Like dinosaurs, gharials are large, slow growing reptiles that lay eggs, which makes them a good model for studying extinct dinosaur species. Our research shows that even with prior knowledge of the sex of the specimen, it can still be difficult to tell male and female gharials apart.