Please don't be offended, but a child you adopt is "your own."
My husband and I received the great gift of our son over 30 years ago, and two years ago he and his wife brought our grandson from the same country. We are not once, but twice blessed. The girls who were born to us later are no more "ours" than their brother, and while we are anxiously waiting for the birth of our son's second child, he is no more our grandchild than his brother from Asia.
As one who considers her children the greatest earthly blessing, I have great respect for those who know that parenting is not what they are called to do. As much as I love my family, I know that I often failed to be the best parent (or sometimes even a good one). Kudos to those who know that other things are their gifts! I am incredibly impressed by you!