A Harvard professor believes it is possible to bring back the Neanderthal species from extinction. To do so you would need “an adventurous surrogate” as he puts it. The Neanderthals have been extinct for more than 30,000 years, but traces of their DNA remain. George Church, a geneticist, says in theory you should be able to clone the DNA and create an embryo, which can be implanted in a surrogate and brought to term. The ethics of such an experiment are murky, to put it mildly.
More about it here [Der Spiegel] and here [New York Daily News].