Ignoring the central message of the Jurassic Park films, some "enterprising" scientists are focusing on efforts to bring back extinct species. In my opinion, this is an unwise and inappropriate endeavor, whether the extinction occurred at the hands of humans or not.
Once we gave up our nomadic lifestyle and turned to cultivation and domestication (both about 10,000 years ago), humans have had a significant effect on the health of other animal populations. Of course, this negative impact greatly increased during the Industrial and Technologic Revolutions as pollution and widespread development destroyed ecosystems. Rather than reversing extinction, a natural component of evolution, we should concentrate on protecting those species that still exist; reducing our population, cutting back on personal consumption, greatly limiting pollution and protecting natural habitat are the primary tools. Nature will heal herself if we get out of her way.
Then again, we have an American President and Administration who are anti-science; they deny climate change, are cutting back (if not eliminating) federal support for green energy industries and even talk of renewing the use of coal in power plants. Unless we reverse the political climate, the extinction of our own species will be greatly accelerated.