Welcome Back, Tazzie
There is a moral issue, an ethical dilemma, where using Science to bring back extinct species is concerned. As was so deftly highlighted in JURASSIC PARK, scientists run the risk of being so enamored with the possibility they COULD bring back an extinct animal that they never stop to ask whether or not they SHOULD. For me, the coolness factor outweighs the ethical questions. Bring back a dinosaur? Hell, yeah! Do it! A Mammoth? I’d pay to see that! A Sabertooth? Yes, please! But I’m not always the mightiest fount of wise decisions, if you’ll pardon the gross understatement.
In cases where we know for a fact that the animal species in question became extinct because of US, because of humans, then the issue becomes less tricky. This would be a case of us correcting a mistake. Nothing unethical about that.
Of all the extinct animals Science might be able to bring back, the most likely candidate is the Thylacine, aka the Tasmanian Tiger. Scientists have now mapped the full Thylacine genome, which is the major first step to cloning one. The technology isn’t available just now, but it will be, sooner rather than later. Of course there are plenty of people who believe the Thylacine isn’t extinct at all, but it wouldn’t hurt to have a backup plan, in case all those sightings over the years have been of GHOSTS of Thylacines.
You can’t clone a ghost, after all.