[Karl Spooner]

Genesis implies very strongly that the Nephilim would have been much more likely to oppose Noah than support him. That the violence and evil of the world of their day was largely perpetrated by the fallen angels and their offspring, the Nephilim.

That's for sure. Satan and his boys were trying to corrupt the Adamic race seedline from which Christ would eventually come. Noah and his family were the only pedigree linkage back to Adam, all the rest were hybrids at the time of the flood.

[Sherman Logan]

Noah and his family were the only pedigree linkage back to Adam, all the rest were hybrids at the time of the flood.

I don't think that conclusion is supported by Genesis. Noah's line of descent is given, but it doesn't say others weren't equally "pure" of blood.

At the very least, Noah and his sons had wives, and their families would have had to be "pure" by your definition.

The Bible speaks of a corrupt and violent culture and society being the problem, not universally corrupt blood lines.

In fact, there is very little support in the Bible, even in the OT, for the notion that God cares much at all about bloodlines. None at all in the NT.