I too am with cj on this.
If I had ever wanted to adopt a child, it too would have been a closed adoption. When the child becomes an adult, it would be up to them to make contact.
Years back, I met this young woman who had given her child up for adoption (she had her problems I think at that time, drugs, whatever). I would overhear her talking to the adoptive mother on the phone, arranging to come for a visit, or a birthday, etc. Just from hearing one side of the conversation, it was really obvious to me that this woman was having regrets at having agreed to this arrangement, but could get herself out of it.
I had casual conversation with this young woman, and to me she seemed totally deluded that she was so welcome by the parents, and was a welcome part of this kids life (she was kinda weird on top of everything else).
I remember thinking "This is really F'd up."
On the other hand, if the adult child decides he/she wants to know the birth parent, they need to respect that the birth parent may not want to be found.
I watched a documentary once where this young woman just HAD to meet her birth mother, who was trying to avoid the whole thing. The birth mother obviously had made a life for herself that did not include a baby she had many years before.
I watched with my jaw on the floor as, after the woman told her through her front door she just didn't feel prepared to deal with this,the young woman stood out in the street and literally yelled out "Carol O'Mally, Carol O'Mally! Come down and talk to me! I'm your daughter, you gave birth to me!"
It didn't seem to dawn on her that just maybe this woman didn't need her neighbors, maybe her husband and her other children to hear this.
What a nightmare.