Why is it that every adult adoptee i know?

I know a couple of adult adoptees very well since they are family members. I think that, for many, being adopted becomes a central part of who they are, it makes them (at least to themselves) seem different from the norm, and makes them think a great deal more about the idea of family. For some, it makes them want to cling to family so much more, makes them value family more than most. It makes them think of family as so much more important and makes them want to have, as an adult, the natural family that they missed out on as children. For others, they probably don't want to re-live the whole experience of family.