Scientists have been mapping the Neanderthal genome and have linked hundreds of their genes to modern humans, proving that there was inter-breeding.
The belief in the past was that this only rarely occurred and that we did not owe much of our genetic inheritance to the "caveman".
The surprise assertion made in this story is that the interbreeding did not take place in Europe, but in the Middle East. (I guess they met on Spring Break.)
There are still questions and disagreement about the claims and the mathematical modelling used to bolster the hypothesis, so I won't be calling the Geico guy "Cuz" just yet.