It seems there are quite a few people who think Genesis 6 is talking about fallen angels being physically intimate with human women and the offspring being Nephilim, or giants.
Now it came to pass, when men began to multiply on the face of the earth, and daughters were born to them, 2 that the sons of God saw the daughters of men, that they were beautiful; and they took wives for themselves of all whom they chose.
3 And the Lord said, “My Spirit shall not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years.” 4 There were giants on the earth in those days, and also afterward, when the sons of God came in to the daughters of men and they bore children to them. Those were the mighty men who were of old, men of renown.
5 Then the Lord saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. 6 And the Lord was sorry that He had made man on the earth, and He was grieved in His heart. 7 So the Lord said, “I will destroy man whom I have created from the face of the earth, both man and beast, creeping thing and birds of the air, for I am sorry that I have made them.” 8 But Noah found grace in the eyes of the Lord. NKJV
This has never set well with me. In fact, I’ve always felt quite uneasy about the matter. It doesn’t make sense, since Jesus said in Luke 20 the following:
34 Jesus answered and said to them, “The sons of this age marry and are given in marriage. 35 But those who are counted worthy to attain that age, and the resurrection from the dead, neither marry nor are given in marriage; 36 nor can they die anymore, for they are equal to the angels and are sons of God, being sons of the resurrection. NKJV
This verse seems to be saying that angels are not sexual beings. How then can the fallen angels produce offspring? It seems they cannot, neither with each other and certainly not with humans.
This link here gives a great explanation of why these “sons of God” are not fallen angels as well as how that title “sons of God” is used in other places of Scripture.
So then, who are these Nephilim, or giants, that are the offspring mentioned in Genesis 6? Was it a kind of genetic mutation as a result of the ‘sons of God’ (believers, followers of Jehovah) lusting after ‘women of the world’?
Furthermore, it stands to reason that if they were the offspring of angels and humans, why aren’t these fallen angels STILL doing this? Why aren’t there any giants today? The end of the age is upon us. We can see satan and his demons working over time. So, wouldn’t they be impregnating as many women as possible? Where are the results of that, if so? Why would the offspring of today look drastically different from those in ancient times?
The link I gave above speaks on this as well and shares my idea of where they came from: perhaps it was a “growth spurt” of two previously isolated tribes of people.
This article (which also gives some really good reasons why ‘sons of God’ are not fallen angels) simply says the giants after the flood were just that….large, strong people.