Ancient aliens mated with primitive woman about 12,000 years ago. As tough as it is to get real physical evidence on the subject we do have clues. A growing number of authors are writing on the subject after years of research.
Ancient texts, archeological finds, Bible passages do point to advanced technology presence many thousands of years ago. Many cultures have stories of 'gods' with phenomenal abilities.
The History Channel is even doing a series on it.
And just on a practical level we can see it all around us. For example, in all the mammal kingdom how is it that only human babies don't fit through the birth canal? Why is there an estimated 1 in 5 children sexually abused in the world.
Why can't we stop that? Why, in the cradle of civilization - the Mesopotamia (now Iraq) is there still the most violence on earth? Why do women women there still entirely cover their bodies? It is written that taller advanced beings mated with ancient women and that the children of this mismatched coupling came out violent and bloodthirsty. Could it be that the genetics just were not all that compatible?
Could it be that humanity is still suffering the brunt of a trauma that at the same time, greatly accelerated human technology but also greatly damaged human ability to function sanely? 12,000 years ago homo sapiens was quite primitive.
Purportedly, all of a sudden agriculture, math, astronomy, architecture, the alphabet, etc. showed up. There doesn't seem to be a gradual implementation of all of these sciences.
When we put it all together we can surmise that the religious stories had it wrong. Mankind was not banished from the Garden of Eden. We were pushed.