Someone posted this video the other day. http://www.youtube.com/watch?v=uStCAKMbnqQ
I wonder if it's like what they're theorizing, when you throw enough genes in there you override the effects of the genes (like in their case lethal combos). In this case fertility issues. Or maybe she's just a fluke fertile female. It'll be interesting to see what the babies turn out like, and then if those desert females will be fertile too.