Many kids will go through a dinosaur-obsessed phase in their childhood, but few follow scientist Ben Novak’s path. Novak, who once won a youth science fair with a project about bringing the dodo back, now leads the development of scientific programs at Revive & Restore, a nonprofit whose mission is the genetic rescue of endangered and extinct species. Having grown up in western North Dakota, where he witnessed the bison, bighorn sheep and elks that had been reintroduced to Theodore Roosevelt National Park, Novak is currently working on a project to use genetic engineering to resurrect the passenger pigeon, which was native to North America and overhunted, leading to extinction in 1914.

BELLA GLADMAN: What can you tell me about de-extinction? 

BEN NOVAK: De-extinction has been going o...