From my own research I have determined that it is near-axiomatic that any fringe theory must connect back to the Sons of God from Genesis 6:1-4, the mysterious fellows better known as the Watchers from the Book of Enoch who stand behind the modern expression of almost every major pseudohistorical claim. They are the warrant for a belief in giants, the prototype of the ancient astronaut, god-kings tied in to the Atlantis theme, and so much more. Sometimes the connections are explicit, and sometimes implicit. Foley falls into the explicit category, citing the Fallen Angels as the foundation for his spiritual views.
I believe, based on Earth’s history and our recent arrival, that it is far more plausible that our species’ major leap forward was triggered by an extra-terrestrial intervention (be those beings physical or what we term spiritual i.e. having no physical body). Genesis states that our species was seeded by God saying ‘we will make man in our image.’ Later in Genesis and in more detail in The book (sic) of Enoch it speaks of how the fallen angels mated with human females which corrupted the genetic line of the human creature that God created and how this angered God. From a logical standpoint, this becomes far more palatable if we consider these fallen angels to be beings from another planet, which may have went (sic) through its own evolutionary path.
But: It always has to be the Watchers! Foley’s unique addition is to tie the Watchers myth into modern concerns about ecology. He worries that humanity’s destructive relationship with the earth occurred because the Watchers’ alien genes disrupted the ecosystem. Foley, in fact, argues that the very fact that humans are destroying the earth’s environment proves that we are alien hybrids, for nature would never create a species that would destroy its environment. This overturns everything we know about evolution—where adaptations occur for the present and lead to change or extinction when they are no longer adequate for the environment—but it represents an unusual wrinkle in the ancient astronaut theory.