I think that's such a generous thing you have done! I would do it for a family member, and dh and I are considering it for my SIL if she can't have a baby by the time we are done with kids. But it can be so emotional. I would want to keep track of that child and know that he/she was being raised well and treated well. You form a bond with that child even if it's not biologically yours.
Best of luck!
7yo: "Mom,I know which man is on a quarter and which on is on a nickel. They both have ponytails, but one man has a collar and the other man is naked. The naked man was our first president."