In collaboration with the North Carolina Museum of Natural Sciences, a team of NC State scientists discovered the presence of a gender-specific reproductive tissue, the medullary bone, in a fossilized T. rex femur. The fossil is 68 million years old and is believed to belong to a Montanan T. rex. This discovery is important to understanding gender differences between meat-eating dinosaurs. The findings were published in the journal Scientific Reports. 

Source: NC State News