I'm not sure to be honest. I think that maybe if the child was in their later teens I'd leave it up to them. Well, I'd probably leave it up to them anyway. I may have raise somebody else's child and they may have raised mine, but if the child has gone this long thinking that one family was theirs, they should have the right to keep going that way. I would definitely tell the child I had been raising, and let them make the decision with the other child about how to involve the families together. It would break my heart to find out that my biological child didn't want to meet me, but at the same time, that's also their decision in my opinion.