As someone who was abandoned as a child and still maintains a pretty good relationship w both parents, I'm sure they are oblivious to the effect that had on me as a child. Nor are they willing to talk about it now. They feel what's done is done and in the past, and don't want the awkwardness of that conversation.
It's cool, but sometimes you wanna cry for that child. As an adult, I've heard the mistake is looking at what happened to you through a childs eyes. Ya can't really ever let it go.