Brandi West
There's a book you should check out. Chariots of the Gods, if I remember correctly. That's one of the things raised in the book. But I think it was more that 'aliens' are our future selves come back in time to adjust things... and that they mated with ancient humans to give us a boost in genetics (thus the missing link) and to help us actualize our potential faster.
Please don't feed into my paranoia. It's not very nice. sweatdrop
Just kidding.