I’ve blogged once before about this point of pseudo-research as it relates to using the Talmud for its justification. In biblical thinking and history, however, the nephilim (who were unusually tall) died out in biblical times. That means there were no modern nephilim in North America of anywhere else.
I know all about the books that (allegedly) chronicle giant clans in North America. They are entirely based on 19th century and early 20th century newspaper reports. While I believe that it’s certainly plausible for someone to come across a human skeleton of unusual height (say, 6’6” on into the 7-foot range, the height of the biblical giants) during those periods (after all, we have such people living among us now – lots of them), I don’t believe there is any solid evidence for a “race” of such people in North America or anywhere else that descend from the nephilim. Nephilim descendants and races in North America is, of course, part of the modern Moundbuilder myth. It is a fact of history that the Moundbuilder myth was created to deny the indigenous native North American races the ability and credit for such creations. While I don’t believe modern nephilim enthusiasts intentionally seek to denigrate the non-white European people in ancient North American, that’s actually where this idea leads – because that was the milieu in which it arose.
Associated with 19th-early 20th century newspaper reports of giant skeletons are certain “findings” of skeletons with “double rows of teeth.” This feature and, supposedly, elongated skulls, is proof of nephilim races. I’ve blogged before about how these skulls have nothing to do with nephilim. I want to shift attention here to the other feature: the “double rows of teeth.” Anthropological archaeologist Andy White has done a good bit of research into these reports. His efforts conclusively show that such language in giant skeleton reports does not refer to skeleton that was double-jawed, or that had four rows of teeth inside the mouth. Rather, “double rows of teeth” is a stock description during the 19th-early 20th era for having two nice rows of teeth (the normal uppers and lowers). Nothing abnormal is indicated by the phrase. I recommend Andy’s excellent research on the matter, specifically:
The long and short of this is, as I have pointed out before, is that it’s important to put forth real, extant data for ideas (and, therefore, to base beliefs on real data). When Christian researchers refuse to do this, they are not being honest. When they lack the research skills to test an idea, they are being inept. I’m grateful for Andy White’s tenacious research on the double-row teeth. It’s a shame that no Christian researcher was as earnest.
 I think the alleged evidence for North American giant “races” is a combination of (1) misidentified fossils; (2) inept researcher bunk; (3) and journalistic contrivance. On the latter, newspapers literally made up stories for readership; the era is infamous for this sort of journalism. See for example, Arthur Wrobel (ed.), Pseudo-Science & Society in the 19th Century America (University Press of Kentucky, 1987). For those who will charge me of “denying the Bible” in regard to this, let me ask for the chapter and verse of the Bible that either requires or says nephilim lived on after the biblical time period. There is no such passage. The modern nephilim race myth has nothing to do with biblical integrity, on this or any other point. It’s a modern myth. On the unusual height of the nephilim and their kin in biblical material, see The Unseen Realm, chs. 12-13, 23-25.
 Archaeologists are well aware of this situation and sensitive to it. The archaeological report that destroyed the non-indigenous moundbuilder myth was published in 1894: Cyrus Thomas, Report on the Mound Explorations of the Bureau of Ethnology (Smithsonian Institution Bureau of Ethnology, 12th Annual Report, Washington, DC. For more recent treatments, see Robert Silverburg, Moundbuilders of Ancient America: The Archaeology of a Myth (New York: Graphic Society, Greenwich, CT, 1965; and Robert Silverburg, The Moundbuilders (Ohio University Press, 1970).