Adopting a child was something I considered for over a year, before God blessed me with my son. I didn't really care so much whose child I would raise, just that I had the chance to raise a child at all. Had it turned out that I could not have my own child (biologically speaking; I clarify because if I ever adopt, that child will be considered my own as well), I would have begun the adoption process. I may still decide to do that- for now, I'm still just trying to get used to raising the baby I have.
I have an uncle who was adopted, and I don't know if it's because he feels like he doesn't really belong, or if it's just his personality, but he keeps his distance from the family, except for his parents (my grandparents). His daughter doesn't have a lot to do with us, either, though again, I don't know that it has anything to do with a lack of blood ties to us. Even biological families drift apart.
Anyway, I think adoption is an all-around beautiful thing; the biological mother who chose not to end a life before it even got started and instead chooses to give her baby away to a family who will love him/her...and the family who takes that baby home with them. I don't see anything wrong with opting not to have your own children and to adopt instead. I believe God knows what He's doing when he brings children into the world who will be adopted by someone else, and He has a plan and a reason for adoptions to happen.