A. There has been many theories as to who the Nephilim were. Unfortunately, there is no proof positive as to who or what they are let alone their excat identity. It is also unknown whether they were a people or a description of a type of people. 

Nephilim is an anglicized word of the Hebrew word נְפִילִים. The etymology of the word is unknown and it only appears three times in two verses in the Old Testament.

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. {Genesis 6:4}

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. {Numbers 13:33}

Many translation like the King James, simply uses the word "Giants" as the english counterpart. Others have anglicize the Hebrew word as Nephilim like the NIV. Other translations, with a more paraphrase-like style have taken much liberty translating the word as “the fallen ones” (YLT) or as far as “children of the supernatural beings” (CEV). 

Since there is really not much to go on, shallow theories have sprung up as to who the Nephilim were, giving birth to all sorts of weird and sometime disturbing conclusion. One of the most popular one, based on the wording of Genesis 6:4, has advanced that the “Daughters of Men” had conceived these supernatural being after having been impregnated by the “Sons of God”, whom it is believed to be fallen angels. Unfortunately there is no biblical basis to support this claim. The very fact that they are called “Sons of God” disqualifies the fallen angels from bearing that title. Jude verse six explains how these angels have “not kept their first estate”, which would also imply that they have also lost their "sons of God" title along their exalted position. Furthermore, if this theory was true, it would also indicate that angels have the capacity to procreate, and that there is most likely female and male genders in the angels. On top of that, in order to engage in this activity of procreation it would require them to be within the confine of marriage and that would contradict the very words of Jesus regarding marriage and angels:

 

30  For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven. {Matthew 22:30}

The identity of the "Sons of God" in this context would refer to the line of those who had remianed faithful to God, i.e.: the descendants of Seth, while the "Daughters of men" would correspond to the descendants from the line of Cain. 

The scripture is silent on the identity of the Nephilim. As to why some translation favours the “giant” translation of the word might be because of its association with the “Anakim.” The Bible associates the Nephilim to the Children of Anak in Numbers 13:33. In many passages, especially in the book of Deuteronomy (1:28, 2:10-11, 21, 9:2), the Anakim are described as being chiefly and especially tall people. In Joshua 11:22, the Children of Anak are said to have been completely driven out from the land Israel and could only be found in Gaza, Gath and Ashdod. It is interesting to note that Goliath, who was considered a giant, nearing nearly ten feet tall, was born in Gath.

Are the Nephilim a race, a tribe or simply really tall people? There is no absolute answers since it has not been clearly revealed in the scripture. We can make certain association that seems to indicate that they are taller than the average men which is probably why they were considered giants especially when considering the link with Goliath of Gath. It is very unlikely that they were something more then mere men, and as diligent Bible student, we should not lose focus on the weightier matter surrounding the events of the flood.

For more information we recommend the following resources:

Studies in Creationism

Dinosaurs and the Flood

Fossils prove a Flood

 

Keywords: Nephilim, Giants, Gath, Ashdod, Gaza, Goliath, sons of God, dauthers of men, angels, fallen angels, procreation, marriage, anakim, children of anak,