John 1:13 – Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God. 

Born implies a birth, blood indicating one’s family lineage or national heritage. Heritage does not bring about the New Birth. The New Birth is not of human origin, but it is spiritual and supernatural, done only by God.

All the children of God are born through the marvelous work of God; all that are adopted are regenerated. It’s not of blood, not the will of the flesh, nor of corruptible seed. We do not become the children of God as we become the children of our natural parents. Grace does not run in the blood as corruption does. It is not produced by the natural power of our own will, it is the grace of God that makes us willing to be His. The rebirth is of God and not of ourselves to be willingly to be transformed, true believers are born of God, and not of the will of man, that is, something done by another individual.