DS has always known that he's adopted. We have a picture of his birthmother on our refrigerator, and he sang "Happy Birthday" to his biological aunt.
It's best when kids know from birth. Sorry, had to say it.
I put together a story book for my son, that basically goes through:
Max & Robyn wanted to be parents.
S was going to have a baby she couldn't care for, so she chose M&R.
M&R went to (State) to meet S and her family.
Jack was born.
We went to a hotel first, then home, where the family welcomed Jack.
We all came back to (State) so the judge could make us a forever family.
Joanna Cole's book "How I Was Adopted" is a great book, as it does cover the "where babies grow" question.
Good luck!
