I wanted to watch the reunion but didn't. So I don't know what said about the adoption what has gone on between when the baby was adopted and the taping of this show. If the birth parents were sending a lot of letters or trying to make contact to the point where it was uncomfortable for the adoptive parents or expressing regret over the adoption then I could see the adoptive parents being hesitant. But I don't know if that's the case or whatever.
It's hard on both couples though who go through an adoption (birth and adoptive) and it can bring up some uncomfortable feelings on both sides I know. It's not easy for anyone involved.