Destroy All Humans!2005

Orthopox:
Now then, I know what you're thinking: what can I, a lowly novice, do to help bring about the destruction of Earth and the inevitable reign of the Furon Empire? Well, I'll tell you. It was in the earliest days of the empire we realized our species was doomed. Eons of waging war on inferior races with unregulated atomic weaponry had mutated our genes. We could not propagate due to a complete and utter lack of genitalia. Fortunately, a Furon ship happened upon Earth on its way back from destroying the Martians. Human society was young and... nubile. Sailors on a foreign planet, letting off steam, one thing led to another. Long story short: every human being alive today has buried deep in his genetic code a strand of Furon DNA. Over the eons, we've learned to clone ourselves, but with each iteration, the information degrades, and the results are increasingly... unpredictable. The Furon genes in humanity's DNA are ancient, uncorrupted. They represent the future of the Furon race. If only we can get at them...