The primary motivation for us adopting kids was theology. Not biology. Because our lives are directly related to what we believe, our theology should lead way to our biography.
I learned from the Scriptures that God is an adoptive father. There are no natural born children into the Kingdom of God. All of us, who are in the family, are here by virtue of adoption.
Note: The video above is good, but if you want the shorter version, then click the button below to read a great article by the same guy.