Just an outsiders perspective (in more than one way). I have many thoughts regarding this topic, but will not share them here.
This thread makes me sad for several reasons. I always wanted 12 kids. Didnt happen. As it turned out, we couldnt have any biological children. Yes, we adopted older children from Korea. They are now 43 and 40 years old.
But we have borne the brunt of many offhand comments from family members and friends that our children are not really ours, and not really part of the family. Another close relative has four boys by three different husbands. She could get pregnant by sneezing. Those children (now adults) are often considered on that side of the family as real family members. 
We have been blessed with five grandchildren and one great-grandchild. But they live 2500 miles away. And we delight in them whenever we can see them (about once every two years).
Ministry to people in all of these kinds of situations (mentioned throughout the thread) requires patience, love, and understanding. Unfortunately Christians often dont exhibit any of those characteristics. And from first-hand experience, I know how that can hurt when the person desires to faithfully serve God.
Okay, so now I bow out.
filo - this makes me unbelievably sad, that family would actually not just make you feel, but actually say, that they are not "real" family....i can't wrap my brain around that.
adopting children is a beautiful, selfless act. if we had not been able to have children, we would have adopted.
i want to take what filo has said, and go a little further with it:
they could not have biological children, and they wanted children, so they adopted. going with the thought process of some here, if they could have had children, they should have just kept having children until they were unable to have them anymore. so, then, should they have kept adopting until they just couldn't adopt anymore?
when my late husband and i had our first child, he started becoming ill (my husband, not my child). by the time our 2nd child came around, he was getting worse. by the time our 2nd child was about 3 1/2, i was the only one working because he could no longer work, because of all his illnesses. his medical report was at least a foot thick. we had discussed having 3 children, but knowing how sick he was, we decided that if something happened to him, it would not be fair to me to leave me to raise 3 all by myself, and so i went on birth control. my husband passed away 1 month after our 2nd child turned 7 years old.
how smart a decision would that have been to just say "oh forget it, whatever will be will be" and have a 3rd child knowing how sick my husband was, and that he was THAT close to death's door? it's called being realistic and responsible. i had a hard enough time with 2 all by myself for the 4 years i was alone, let alone thinking of trying to do it with 3, it would have been almost impossible.
God knows why we make the decisions we make. He knows the plans He has for us, and He uses the decisions we make, whether they be good decisions or massive screw ups to His Glory.
do NOT look down on someone for the decisions they make, for what is right for THEIR family.