... with ancient humans. Some argue that the word Angels as used below, actually means "those who decended from above" or extraterrestrials
"And it came to pass when the children of men had multiplied that in those days were born unto
them beautiful and comely daughters. And the angels, the children of the heaven, saw and lusted after them, and said to one another: 'Come, let us choose us wives from among the children of men"
you can read the entire book of enoch here
http://www.heaven.net.nz/writings/thebookofenoch.htm