Before you start knocking on doors, DO make sure that the mother wants to have contact with the children. By now, she may have a new family and a partner who may not know of the previous children. You could break that new family up by your contact....
... but you MUST respect her wishes.
Terri - you really feel that way? Wouldn't that be a relationship built on a lie? What about the wishes of her new partner to know the full truth about his fiance/wife, etc.? We are not talking about who she was with in the past, etc. Who cares. We are talking about a child she gave birth to. A pretty big deal, wouldnt you say?
I mean if I was her new partner I think I'd have liked to know the full truth, nothing wrong with putting up a child for adoption if that seemed like the right idea at the time. However to keep it secret from the new partner seems somewhat sickening to me... What else could she be hiding?? Sounds like a very unhealthy situation.