An excellent question. The scientific name of Oviraptor is a great example of how theories concerning dinosaur lifestyles are in a constant state of flux. It was originally proposed that Oviraptor was an egg predator based on a variety of fossil discoveries, but recent evidence suggests that Oviraptor actually brooded its clutch and was a nurturer, not an egg-stealer. Regarding the question concerning paternal vs. maternal care of offspring by T. rex, this is a difficult question to answer. Because of the overall rarity of T. rex fossils, little to no evidence currently exists to favor the participation of one parent over the other in the child-rearing task. Many modern birds exercise biparental care of the newly hatched young, meaning that both parents contribute to the rearing process. Based on what is proposed regarding dinosaur evolution, it would not be too surprising to learn that both parents contributed in child rearing, but this idea is still heavily debated. In reference to your wishbone question, this has a more straightforward answer. The wishbone is a skeletal modification for flight and is not related to a species ability to exercise parental care. Birds simply cannot fly without wishbones. The flexible U-shaped strut formed by the fused collarbones braces the entire shoulder against the stresses of flapping. Based on the fact that many of the early bird-like dinosaurs had poorly developed collarbones, it would not be surprising that this was also the case with Oviraptor whose forelimbs were proportionally way too small to be used in flight. Many of these species lived before the time of archaeopteryx, who had evolved a modern grade of wishbone, with long left and right collarbones fused together beneath the chest. Based on what I've discussed above and what you know regarding the forelimb anatomy of T. rex, do you think that this species had a wishbone? I'm glad to hear about your interest in dinosaurs, as they truly were magnificent creatures. One of my all-time favorite dinosaur species is of the genus Troodon. See how much information you can find regarding this amazing predator. Another one of favorites is the Pterosaur, Ornithocheirus, which is believed to be the largest flying animal of all time. Ornithocheirus had a wingspan up to 40 feet across and was the size of a small airplane. This is an impossible animal; the calculations show that no flying animals could be so big. And yet, it existed and it flew.

I was lucky enough to take a class from Jack Horner, one of the well known dinosaur scientists.We looked at a lot of prehistoric bones. The big question is how anyone can use fossils to tell what an animal did (its behavior). We have fossilized bones, plants, eggs, and even fossilized droppings, but we can't go back in time to see whether animals cared for their young or not. We have to take fossil evidence and make our best guess (this is called a "hypothesis"). So let's say you find the bones of an adult near a nest of eggs. Was it chance (just passing by)? Was it trying to steal and eat the eggs? Was it sitting on them? That's tough to say. One kind of evidence that scientists use is the bones of the baby dinosaurs. They ask, "are the bones of a newly-hatched baby strong enough for the baby to have found its own food?" If not, they figure that something had to bring it food, most likely its mother. Would a dinosaur have sat on its eggs? Most reptiles don't, as you read on the site you mentioned, but most birds do. Would it be more likely for the dinosaurs to have sat on the eggs if they were warm-blooded? There is still a lot of debate about these things. Can you think of a piece of evidence that would answer any of these questions? Maybe you will find this evidence some day.
Thanks for asking,