Loyal
I think we get the wrong idea of what it means to be "adopted" as a son of God. the word "adoption" is made up of two words. The first is, "ad", which means "to", and the next part is, "option" which means "choose". Together they mean "to choose". We were chosen to be in Christ before the foundation of the world, not that we came form some body else's family.
Eph 1:4 According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:
We were born again by the incorruptible seed of the Word of God. The seed of God is God. God lives inside us as he is that seed, and it has come alive in us. We are truly God's off spring!!
1Peter 1:23 Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever.
No wonder we are going to live forever, because God in us lives forever, who has become our new life.
We are NOT "the" Son of God, but we are "a" son of God because of the life we have in us.