Genesis 6:2
[SUP]2 [/SUP]that the sons of God saw that the daughters of men were beautiful; and they took wives for themselves, whomever they chose.
I do not see anything in my Bible that they were great mighty men, giants. This part in not in the Scriptures. Also the 'sons of God' cannot be Angels because Angels would not commit these sins. Also 'evil angels' are not designated as 'sons of God'.
Therefore it has to be the children from Adam that this verse talks about.