(A snippet from my Sci-Fi blog, which could be useful someday…)
I had once preferred a simple definition, myself: “a son of Adam”. But that isn’t a good Biblical definition, for two reasons. First, from Genesis…
God said, “Let us make man in our image, after our likeness. Let them have dominion over the fish of the sea, over the birds of the sky, over the livestock, over all the earth, and over every creeping thing that creeps on the earth.” God created man in his own image. In his own image he created him. Male and female he created them. God blessed them and said to them, “Be fruitful, and multiply. Fill the earth, and subdue it. Have dominion over the fish of the sea, over the birds of the sky, and over every living thing that moves upon the earth” (Genesis 1:26–28).From the Unlocked Literal Bible translation
Put simply: the image of God we manifest is shown by our actions, by filling, subduing, and having dominion over the earth.
(And not by having The Right Men gain dominion over other men, as the statist Greeks or Muslims would have it.)
The focus is on actions. Not genetic lineage.
And secondly: the natural sons of Adam are disinherited, and damned to hell. Only the adopted sons of God, led by the only begotten son of God, Jesus Christ, have a future worth talking about.
So, people are defined by actions, not genetics. And salvation is determined by adoption by God, and not by our own will or origins.