The adoption agency will require you to tell your parents, siblings and immediate family members besides your neighbours as part of the process. Rightly so, for they understand that even if you do not live as a joint family, a child’s happy adjustment to this new life will depend in part on how open and accepting your families and neighbours will be. Of course, you can’t control how everyone thinks and how they will choose to react to this news, but you must give them this news in the best possible way to make it easy for them to accept this new phase in your lives and more importantly your child.
So make a list of all the people in you life under the following categories- immediate families, relatives, friends- old and new, colleagues, neighbours, those who work for you or come to deliver stuff to your house and decide on the extent of information you would like to give each of them.
There really is no point leaving anyone out because then the only option you are giving them, when they see you with your new baby, is to ask you uncomfortable questions or gossip behind your back and spread untruthful information.