Among the sensational topics of Bible prophecy is the idea that hybrid human-angels called Nephilim are again on earth as a sign we are close to the return of Christ. Jesus did say, "as it was in the days of Noah, so it will be at the coming of the Son of Man" (Matthew 24:37, NIV). Among the characteristics of the "days of Noah" we find this: "The Nephilim were on the earth in those days, and also afterward, when the sons of God went to the daughters of humans and had children by them. They were the heroes of old, men of renown" (Genesis 6:4). It is clear that the term "sons of God" has to refer to angels because this is even more clear the other times it is used in the Old Testament: Job 1:6, 2:1, 38:7.
It is likely the Greek gods were inspired by the Nephilim since they were, "heroes of old, men of renown." Note that Genesis 6:4 says the Nephilim were also on earth after the flood and we see this when the Israelites conducted a reconnaissance in the Promised Land prior to occupying it: "we saw the Nephilim there (the descendants of Anak come from the Nephilim). We seemed like grasshoppers in our own eyes, and we looked the same to them" (Numbers 13:33). King David likely dueled with a Nephilim named Goliath who was described as being over nine feet tall (1 Samuel 17:4). Today's tallest basketball players are at least foot and a half shorter, but who knows, some may be Nephilim.
The problem I have with the idea that the Nephilim were hybrid human-angels is that angels don't procreate. Jesus told us, "at the resurrection people will neither marry nor be given in marriage; they will be like the angels in heaven" (Matthew 22:30). We also know that angels are non-corporeal spirit-beings because Hebrews 1:7 says, "in speaking of the angels he says, 'He makes his angels spirits, and his servants flames of fire.'" Angels are like fire in that they can be seen but do not have physical bodies. Yes, angels can manifest themselves as appearing to have physical bodies because Hebrews 13:2 says, "do not forget to show hospitality to strangers, for by so doing some people have shown hospitality to angels without knowing it." However, angelic spirit-beings do not have physical bodies as Jesus demonstrated after He was resurrected by inviting His disciples to touch Him to verify that He had a physical body (Luke 24:38-39).
So if angels are non-corporeal and can not procreate, how do we explain Genesis 6:4 where it looks like they had children by human mothers? We do know from Scripture that fallen angels, or demons, can possess people who don't have the presence of the Holy Spirit. And these possessions can involve many demons at the same time, see Luke 8:26-33 & 11:24-26. So it seems likely that the progeny of the fallen angels during Noah's day were children born of possessed women (and men) who then grew up being possessed from birth.
But how do we account for the fact that the Nephilim were described as physical giants? And we have Genesis 6:9 which sheds light on why God chose Noah saying he, "was a just man, perfect in his generations" (NKJV). Many have concluded that Noah's genetic line from which the Messiah would have to come was not tainted with the alterations that produced the Nephilim. One very likely possibility then is that the giants of old were the result of genetic manipulation. The fallen angels certainly could have had a role in tweaking the human genome to produce giants because they were highly intelligent beings. Satan is described as being "full of wisdom" prior to his rebellion in Ezekiel 28:12 (NIV).
In our day, it is just a matter of time before we see wide-spread gene modification happening in humans. The Chinese have already been dabbling in it because they have fewer ethical restrictions than in most Western nations. But this will only serve to break down the human gene editing barriers worldwide in the interest of staying competitive. Manipulating the human genome holds the promise of getting rid of genetic diseases and undesirable characteristics. At least one progressive visionary is already dreaming of the day when humans can be given certain desirable animal characteristics as a way to combat global warming. If people are just evolved animals, why not give evolution an assist by tweaking the human genome? Every day we learn of some new depth the debased mind wants mankind to plunge into.
We know that fallen angels left their spiritual domain to mix it up with mankind prior to God's judgment of the flood (Jude 6), so we can expect something like that to also happen prior to God's judgment of the Tribulation. This probably will not result in giants walking the earth this time though we shouldn't rule that out. If we start seeing nine-foot basketball players, we probably should take that as a sign. However, the coming of the new Nephilim will certainly have god-like characteristics as "the heroes of old, men of renown." Jesus warned us that, "false messiahs and false prophets will appear and perform great signs and wonders to deceive, if possible, even the elect" (Matthew 24:24). Indeed, the Antichrist and False Prophet will demonstrate great powers during the Tribulation (Revelation 13:2-17).
We live in amazing times when every day there are new developments that show how close we are to the end of the Age. Even so, come Lord Jesus, this world sorely needs you.