The Apocryphal books of Enoch, 2 Esdras, Genesis Aprocryphon and Jasher support the Genesis story, adding that the sin of the angels grew to include genetic modification of animals as well as humans. The Book of Jasher, mentioned in the Bible in Joshua 10:13 and 2 Samuel 1:18, says, "After the fallen angels went into the daughters of men, the sons of men taught the mixture of animals of one species with the other, in order to provoke the Lord"(4:18). This clear reference to the Genesis 6 record illustrates that "animals" were included in whatever cross-species experiments were being conducted, and that this activity resulted in judgment from God. The Book of Enoch also supports this record, saying that after the fallen angels merged their DNA with women, they "began to sin against birds, and beasts, and reptiles, and fish" (7:5,6). The Old Testament contains associated reference to genetic mutations, which developed among humans following this activity, including unusual size, physical strength, six fingers, six toes, animal appetite for blood and even lion-like features among men (2 Sam 21:20; 23:20).

What if, by corrupting the species barrier in which each creature was to recreate after its "own kind," Watchers had successfully mingled human-animal DNA and combined the hereditary traits of different species into a single new mutation? An entirely new being—Nephilim—might have suddenly possessed the combined intelligence and instincts (seeing, hearing, smelling, reacting to the environment) of several life forms and in ways unfamiliar to creation.

Will modern biotechnology resurrect Nephilim?