Lots of dinosaur fossils are being found everyday. Fossils found are usually not complete. This makes it harder to obtain accurate information about the dinosaur. There are almost-complete dinosaur fossil, but even with the skeleton it is hard to determine the sex of the reptile.
With most animals of the world, figuring out the sex is pretty easy. All one has to do is observe their behavior and look at the sex organ. But with dinosaurs its actually pretty sophisticated. Since they are extinct now, it’s not possible to observe them. Also, sex organs made of soft tissues decay and does not fossilize like bone, so that is also out of question. To make matter more complicated, most paleontologists think that dinosaurs, like birds, used one opening for both reproduction and excretion. So even if scientists find well preserved skin with dinosaur they might still be confused.
Sometime fossils are found with eggs. This might in first look make it seem that the dinosaur is female, but the fact that sometimes male does the brooding, like penguins, makes it later unclear. Another unclear method of distinguishing sex is the sexual dimorphism. Here we take in account that dinosaurs may need special features, like long necks or horns, to attract mates. But it’s unclear because it cannot be determined whether female attracted males or the other way around.
DNA is also a general way of figuring out sex. But this method doest not work on many of these ancient reptiles since their sex is not determined by X or Y chromosomes, like us mammals, but is determined by the temperature of their egg! Also, the DNA breaks down during fossilization.
There is a working way of determining the sex, but it only works if the dinosaur is female and pregnant. In female birds,
medullary bone lines the interior or medullary cavity, of bones. Birds use this bone as a reservoir for the calcium they need to produce eggshells. So the same theory is applied on the dinosaur. Unfortunately, researchers need to break inside the bone to perform this method and just because the result of the test is negative it does not necessarily means that the dinosaur is male since it is possible that it is a non-pregnant female.
Science is still advancing. So even if there is no accurate way to distinguish male and female dinosaurs now, someday there will be. With so much new dinosaurs being found, that day may be close.
