According to paleontologist Jordan Mallon, the answer may not be as simple as scientists have thought. For decades paleontologists have assumed that dinosaurs exhibited sexual dimorphism. The term “sexual dimorphism” basically means that girls and boys of a species do not look the same, like peacocks and lions. Jordan Mallon on the other hand argues that the fossil record doesn’t support this in the case of dinosaurs.
Despite several journals having been written on the topic, Jordan points out that the data in these journals, while extensive, does not statistically prove that certain species of dinosaur have notable skeletal differences between males and females. Most of these journals make comparisons of bone size or features such as frills or nose horns.
Jordan accuses too many paleontologists of assuming sexual dimorphism exists in dinosaurs and then searching for evidence to back up the claim, which is not how science should function.
“I’m not saying that dinosaurs were not dimorphic, but I am saying that there’s no existing fossil evidence to suggest that they were. The jury is still out,” says paleontologist Jordan Mallon.
There are some cases though where evidence may be present. For example, in modern birds the females have a layer of medullary bone in some sections of the skeletons which contribute to the calcium used for egg production. Egg production of course is strictly a female trait so there is certainly a possibility that several avian and avian related dinosaurs exhibit medullary bone which would peg a particular specimen as female.
This type of evidence is rare however and it will be a while before the mystery of dinosaur gender is truly unraveled.