The bloodline from a Christian perspective:
It spans all ethnicity/races. Basically, purity of the bloodline could be ascertained by what part of the conscience is intact. Narcissists do feel - for themselves, they are stuck in a hall of mirrors. All cats are grey at night.
A psychopath is a SADIST, well they look human, but that's it. SUBHUMAN. NOT OF THE SAME SPECIES, LITERALLY.
That is the only division between those of flesh and blood. From a Christian perspective - the sheep/the goats, the wheat/tares. Remember, Jesus did not say he was coming to unite - but to divide.
That link is not a christian perpective but a catholic one. Thier are some majior flaws in thier reasoning as well.
First of all if trees meant people and fruit means sex then God told Adam he could have sez with all the trees in the garden except the tree of Knowledge. And we all know what god thinks of homosexuality (this is before Eve was formed).
Gen 2:9 And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil.
Gen 2:16 And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat:
Gen 2:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
Gen 2:18 And the LORD God said, [It is] not good that the man should be alone; I will make him an help meet for him.
Its plain in the wording that it was a food to be eaten not symbolic as well
Gen 3:6 And when the woman saw that the tree [was] good for food, and that it [was] pleasant to the eyes, and a tree to be desired to make [one] wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat.
Though I do beleive thier may be some people with tainted bloodlines the seed of HaSatan is generaly spiritual (demonic)