God has given us space to “choose this day whom we will serve” as Joshua says (Joshua 24:15). But those who are born naturally also have to be adopted into God’s family no matter their family tree. As Jesus says in John chapter 3, everyone must be “born again” to enter God’s kingdom. This spiritual birth or adoption is much more binding than natural birth.
I was adopted at 14 by my own request. I asked my natural parents to relinquish their parental rights and signed my own adoption papers with my new family. So I understand the concept very well. Adoption means that the former family is not yours anymore. You have a new one. Even your birth certificate is changed to reflect the change in families.
I don’t agree with people who were adopted young and later search for their birth parents. Birth parents that let go of their offspring are just egg donors and sperm donors to me. They have nothing to do with the blood, sweat and tears of raising a child. So in my view they are not really the parents. Adoption is permanent, and at the age I was adopted I had the privilege of choosing a new family. They are more than merely genetic influences for me.
When we are adopted into God’s family, it is the same. We make the choice, and it’s permanent. God takes us as His children, with all of our faults and failures. He chooses us even if we are not the model child. Like my adoptive parents, He sticks with us through our teenage years when we know everything but are still dumber than rocks. He is patient, loving, and kind, and requires that we live by the rules of His household. We are treated just like any other son or daughter, protected and nourished and disciplined to stay on the right path.
From Whole Bible Christianity chapter 2 Salvation