Who Were the Sons of God in Genesis 6?

Genesis 6:1-4 reads as follows:

When men began to increase in number on the earth and daughters were born to them, the sons of God saw that the daughters of men were beautiful, and they married any of them they chose. Then the Lord said, "My Spirit will not contend with man forever, for he is mortal; his days will be a hundred and twenty years." The Nephilim were on the earth in those days and also afterward when the sons of God went to the daughters of men and had children by them. They were the heroes of old, men of renown (NIV, italics added).

The term "sons of God" seems to be ambiguous in this context, so naturally there is disagreement over the interpretation of this passage.

Many Christians believe that the sons of God were angels. They believe that 1 Corinthians 11:10 and 2 Peter 2:4 allude to Genesis 6:1-4, lending support to their conclusion. They also point out that the term "sons of God" is sometimes interchanged with angels, depending on the Old Testament Hebrew manuscripts. For example, Job 1:6 in the NIV reads, "One day the angels came to present themselves before the Lord, and Satan also came with them." But in the KJV, the same passage reads, "Now there was a day when the sons of God came to present themselves before the Lord, and Satan came also among them (Italics added).

However I question that conclusion because I see many holes in it. While it is clear that the "sons of God" in Job 1:6 are angels, John 1:12 also reads "But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name" (KJV, italics added). There is absolutely no biblical foundation for the belief that believers become angels when they die!

Understand also the nature of angels (and demons alike). They are spirits; they do not have reproductive organs. While angels can appear in the form of human beings, there is no Scriptural indication that they can reproduce. Furthermore, if the sons of God were angels, then what were the Nephilim (their offspring in Gen. 6:4); a type of human-angelic hybrid?!

Finally and most importantly, Jesus said, "At the resurrection people will neither marry nor be given in marriage; they will be like the angels in heaven" (Matt. 22:30 NIV). What are we to infer? Can Jesus' words be any more clear here? Remember, Genesis 6:2 states that the sons of God married the daughters of men.

I believe Genesis 6:1-4 is merely referring to godly men (believers) who wrongfully inter-married with ungodly women (unbelievers). Genesis 4 and 5 seem (to me) to contrast between the wicked descendants of Cain and the godly descendants of Seth. So it is possible that the two families did not intermarry until Chapter 6, then provoke God's wrath (2 Cor. 6:14). As firmly as I hold to this interpretation, there are still many Christians who disagree. That does not disturb me because this is a peripheral Christian debate which does not call for division.