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. (Genesis 6:4)
My wife just rolls her eyes when I tune the TV to Ancient Aliens on the History Channel. “Why do you watch that junk?” is her common refrain. Well, except for their godless frame of reference, there is actually a certain amount of truth behind much of what they have to say. After all, every good lie carries a certain element of truth. According to the “ancient alien theorists” (AATs), aliens were on the earth long ago and taught evolving humans their technology in order to help the human race evolve. The humans in turn often worshipped them as gods. These ancient aliens also built the monumental megaliths that we see all over the world, like Stonehenge, Machu Picchu and others.
There exists in the Evangelical community a somewhat fringe element along the line of these AATs. The likes of L.A. Marzulli, Steve Quayle, and Timothy Alberino appear as frequent guests on end-time prophecy shows on the internet like Prophecy Watchers, Prophecy in the News, SkyWatch TV, and others. I say “fringe” because most Christian Evangelicals are either unaware or ambivalent of the subject of the pre-Flood Nephilim, even as it pertains to end-time prophecy. Like the AATs, these Christian “giant” chasers believe that, before the Global Flood (Genesis 6-9), giants existed on earth. However, they originate from God, as alluded to in Genesis 6:1-4, rather than being from other parts of the universe. The ancient aliens, therefore, are fallen angels (demons) that succeeded in corrupting the human race and causing God to rain judgment down upon all the earth. Only Noah and his family were pure enough in their genetic makeup to be saved from the wrath of God.
“There were giants [Nephilim] 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” (Genesis 6:4).
“Nephilim,” comes from the Hebrew nephı̂yl, meaning “a feller, a bully, or a tyrant.” It comes from the root word nâphal, a verb meaning, “to fall.” They were the products of unsanctioned unions between “the sons of God” (bene elohim, i.e., (fallen) angels) and the “daughters of men” – human women. How these fallen angels were able to mate with human women, we do not know or understand. Jesus said, “For in the resurrection they [i.e. humans] neither marry, nor are given in marriage, but are as the angels of God in heaven” (Matthew 22:30). According to this, angels cannot breed, nor do they breed. Perhaps these demons were doing DNA manipulation on these women to produce the Nephilim. Maybe they took possession of human men who were able to copulate with human women and thereby alter their DNA. We simply do not know, and God did not provide that detail in His Word. When questions like this come up, we must remember, “The secret things belong unto the LORD our God: but those things which are revealed belong unto us and to our children for ever, that we may do all the words of this law” (Deuteronomy 29:29).
It is interesting to note what Jesus said: “And as it was in the days of Noe, so shall it be also in the days of the Son of man” (Luke 17:26). Modern scientists are doing gene manipulation with the pretense of eradicating heritable diseases. They are also boasting that they can create “designer babies.” There is talk of creating “super soldiers” through genetic engineering. Of course, in the US, these kinds of experiments are highly regulated and restricted, but other countries do not share our ethics. Hitler had his scientists working on creating a super race. Therefore, the return of Nephilim “after” (Genesis 6:4) is not so farfetched, especially with our rapidly growing and unchecked technological advancements.
I have no real problem with those who chase after “giants;” that is fine, I suppose. Our Lord’s return is close at hand. We should focus more on the certainty and imminence of His second coming rather than on pre-flood giants. In His statement on the days of Noah, Jesus also said that “They did eat, they drank, they married wives, they were given in marriage, until the day that Noe entered into the ark, and the flood came, and destroyed them all” (Luke 17:27). In other words, they were so distracted with the mundane things of life that when the flood came, they were not expecting it. This is how I feel about all this preoccupation with giants, Nephilim, aliens, UFOs, etc. These things, while interesting, are a distraction from the main event that is just around the corner. We should focus more on the Lord’s return and do all we can, like Noah, to warn others of what is ahead in order to save as many as possible from the wrath of God that will surely come on an unbelieving world. The Nephilim will return, but I do not expect to be here when they show up!
 “The Exceptions” https://erniecarrasco.com/2014/02/10/the-exceptions/
 “Designer babies: an ethical horror waiting to happen?” https://www.theguardian.com/science/2017/jan/08/designer-babies-ethical-horror-waiting-to-happen
 “U.S. Super Soldiers Of The Future Will Be Genetically Modified Transhumans Capable Of Superhuman Feats” http://endoftheamericandream.com/archives/u-s-super-soldiers-of-the-future-will-be-genetically-modified-transhumans-capable-of-superhuman-feats
 “Not Expecting to Die” https://erniecarrasco.com/2017/07/30/not-expecting-to-die/