just WHO were sons of god in Genesis who co mingled with Women ?

[Gabriel Elijah]

"Son of God" can have different meanings in different contexts.
It could mean Jesus Christ.
It could mean a righteous/redeemed human who serves God.
It could mean an angel.
It could mean a pagan ruler regarded by his subjects as divine.

Very good point—but the real question shouldn’t be what does “son of God” mean every where in Scripture, but what does the Hebrew bene elohim mean—the phase used in Gen 6. And how is this particular phrase used elsewhere in biblical thought (or even in other Jewish writings).