I was adopted into a similar race family, so I can't say I understand completely, but I do understand not talking about adoption very much. I knew as a child I was adopted, but it wasn't something discussed much. As I got older though, I did finally talk to my parents about it and come to find out, they are as curious about my roots as me. Now they are combing the internet looking for clues. My mom even sends articles she finds and they sent all the paperwork they had from my adoption.
If you feel like searching, then you should. If you feel like discovering more about you ethnic background and culture then you should as well. I wouldn't recommend trying to hide it from your parents but understand that if they don't like it or get upset, it's their issue not yours. You need to do what is right for you and from your post, that is finding out more and hopefully they will see how important it is to a member of their family and help you along.
