Two views come to mind.
FIRST
Gen. 6:1-2 And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.
Does Jude have anything to add?: And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day. Evan as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the vengeance of eternal fire.
Gen. 6:4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown. What does it mean, 'giants?' How are giants related to the end times? The passages reads, 'and also after that.' What do you make of that?
Num. 13:33 And there we saw the giants, the sons of Anak, which come of the giants: and we were in our own sight as grasshoppers, and so we were in their sight. And lets not forget about Goliath.
http://www.khouse.org/articles/1996/43/
http://www.khouse.org/articles/1997/110/
http://www.khouse.org/articles/1997/22/
Really, what do you think the days of Noah were like?
When the Bible tells us Noah was perfect in his generations (tamin=without blemish, physical perfection, and not moral. Ex. 12:5; 29:1. Lev. 1:3, 10; 3:1, 6; 4:3, 23, 28, 32; 5:15, 18; 6:6; 9:2, 3; 14:10; 22:19; 23:12, 18. Num. 6:14; 28:19, 31; 29:2, 8, 13, 20, 23, 29, 32, 36. Ezek. 43:22, 23, 25; 45:18, 23; 46:4, 6, 13) do you believe he was morally pure or physically pure? And what do you base this on?
SECOND
John Gill wrote,
Noah was a just man; not only before men, but in the sight of God; and not by his own works of righteousness, for no man is just by them before God, but by the righteousness of the promised seed, the Messiah; for he "became heir of the righteousness which is by faith", Heb_11:7 the righteousness which was to be brought in by the Son of God, and which was revealed to him from faith to faith; and which by faith he received and lived upon, as every just man does, and believed in as his justifying righteousness before God; though he also lived a holy and righteous conversation before men, which may rather be intended in the next part of his character:
and perfect in his generations; not that he was perfectly holy, or free from sin, but was a partaker of the true grace of God; was sincere and upright in heart and life; lived an unblemished life and conversation, untainted with the gross corruptions of that age he lived in, which he escaped through the knowledge, grace, and fear of God; and therefore it is added, that he was holy, upright, and blameless "in his generations": among the men of the several generations he lived in, as in the generation before the flood, which was very corrupt indeed, and which corruption was the cause of that; and in the generation after the flood: or "in his ages" (w), in the several stages of his life, in youth and in old age; he was throughout the whole course of his life a holy good man."
Gen 6:4 - There were giants in the earth in those days,.... That is, in the days before the sons of God took the daughters of men for wives, in such a general manner as before declared, or before the declension and apostasy became so universal; even in the times of Jared, as the Arabic writers (n) understand it, who say that these giants were begotten on the daughters of Cain by the children of Seth, who went down from the mountain to them in the days of Jared, see Gen_5:20 the word "Nephilim" comes from a word which signifies to fall; and these might be so called, either because they made their fear to fall upon men, or men, through fear, to fall before them, because of their height and strength; or rather because they fell and rushed on men with great violence, and oppressed them in a cruel and tyrannical manner; or, as some think, because they fell off and were apostates from the true religion, which is much better than to understand them of apostate angels, whom the Targum of Jonathan mentions by name, and calls them Schanchazai and Uziel, who fell from heaven, and were in the earth in those days:
and also after that, which shows that the preceding clause respects giants in former times:
when the sons of God came in unto the daughters of men, came into their houses and chambers, and lay with them:
and they bare children unto them, or giants unto them, as may be supplied from the former clause; for the sense is, as there were giants before this general defection, so there were at this time, when there was a mixture of the Cainites and Sethites; which were the offspring of the sons of God, or posterity of Seth, mixing with the daughters of men, or the posterity of Cain; for this is not to be understood after the flood, as Aben Ezra, Ben Melech; and so they are described in the following words:
the same became mighty men; for tallness and strength, for power and dominion, for tyranny and oppression:
which were of old: like those that were of old before; or who in after times were spoken of, as in the days of old:
men of renown, or "of name" (o); whose names were often made mention of, both for their size and for their wickedness; they were much talked of, and extolled for their exploits, and even wicked ones: they were famous men, or rather infamous; for some men get a name in the world, not for their goodness, but for their greatness, and sometimes for their great wickedness; which sense is countenanced by what follows: that there were giants in these early times is confirmed by the testimony of many Heathen writers; such were the Titans that made war against Saturn, begotten by Ouranus, who were not only of bulky bodies, but of invincible strength, as Apollodorus (p) relates, and Berosus (q) speaks of a city about Lebanon, called Enos, which was a city of giants, who were men of vast bodies, and of great strength, inventors of arms and music, were cannibals, and exceedingly debauched.
(n) Elmacinus & Patricides apud Hottinger, p. 235, 236. (o) אנשי השם "viri nominis", Montanus. (p) De Origine Deorum, l. 1. p. 14. (q) Antiqu. l. 1. fol. 5. 2. vid. Horat. Carmin, l. 2. Ode. 19. Ovid Metamorph. l. 1. Fab. 1.
_______________________________________
According to the note in my Reformation Study Bible on Gen. 6:2, "These have been identified as Sethites [the traditional Christian interpretation], as angels [the earliest Jewish interpretation; cf. Job 1:6], and as royal tyrannical successors to Lamech who gathered harems [porposed by rabbis of the second-century ad]. All three interpretations can be defended linguistically. On the surface, the first interpretation best fits the immediate preceding context [a contrast of the curse-laden line of Cain with godly line of Seth], but it fails to explain adequately how "daughter of men" refers specifically to Cainite women. The second view has ancient support, but seems to contradict Jesus' statement that angels do not marry [Mark 12:25] and does not explain why the focus is on mortals [v. 3] and the judgement on them [vv.5-7]. The third interpratation best explains the phrase "of all whom they chose" [12:10-20; 20:1; 1 Sam. 11] but lacks as much ancient support. The best solution is probably a combination of the last two. These human offspring are also the spiritual offspring of Satan [3:15], empowered by demons [cf. Deut. 32:17]
NOW, since then I've had to reconsider. Can angels procreate, are they male nor female or are they spirit beings? Who were these "giants?"
Peace,
jm