Its an idea I've toyed with, and theres evidence present in many religious writings, and if any religious writings were true an Alien species would be the most reasonable explanation for our existence.

But the question follows the same logic as any other question: How do we know we're not products of God? How do we know there's not a golden teapot in orbit around Mars?

The question is useless without reason. I can somewhat see where your coming from, but it has no real relation to the idea of us being products our being watched over by alien life. Our semi-systematic behavior in many cases can be directly compared to that of other animals on the planet, but more specifically viruses. Its like asking, how do we know that humans aren't just really complex viruses?

The idea has merit, but you're not pursuing it properly.