To be fair, that was hand waved away in the books, if I remember correctly, as the end result of a colossal mistake on the part of the scientists. Their mistake was substituting certain animal genes to replace broken sections in dinosaur DNA, resulting in dinosaurs that weren't "pure" dinosaurs anymore. There's a LOT of species on this world that can undergo Parthenogenesis, which is what it's called when some mothers of certain species can give birth to their clones. IRL, lots of fish, plants, and whatnot can perform Parthenogenesis when there's not enough males to keep the population up. It has some advantages for the animals that can do it, but also a lot of drawbacks. If the animals in question accidentally have all their males die off, they will lose their ability to adapt over time, and become genetically "stranded", because when moms give birth through Parthenogenesis, every baby (in some species that do it) is essentially an exact copy of the mother. Some species of trees are this way now, because their males died out, and the females are thus limited to Parthenogenesis only. Some species of Whiptail Lizards had their males completely die out, so the females lay unfertilized eggs that develop into exact clonal copes of their mother. In such cases, they are still alive, but not exactly adapting over time, so they are VERY vulnerable to disease. If a new virus comes along that can wipe out one of them, it can likely wipe out ALL of them, so clearly sexual reproduction is very important to have variety, which these genetically stranded species now lack... Anyways, I went on a long ass tangent, there, but just wanted to say that story "Jurassic Park" is basically deriving the dinosaur's ability to give birth to their clones off the fact that the scientists stupidly used DNA from animals that COULD actually give birth to their clones to repair dinosaur DNA. So, it does track, if one wants a little "realism" from a story about dinosaurs being brought back to life. Also, most of the dinosaurs portrayed in Jurassic Park came from other time periods, like the Cretaceous Period. I can forgive them for their error with the name, though, as Cretaceous Park probably doesn't roll off the tongue as neatly as Jurassic.