Making contact with son's bio mother... how to go about it?

I live in va & all adoptions are closed. My 4 yr old son is in foster care & I've been considering letting. the foster family adopt. My concern is that I want to be involved but cannot b guaranteed that. I think u should definatly contact her. Be honest with her. I'm sure there is not a day that goes by that she doesn't think of him. He is after all a part of her. If she doesn't respond or it doesn't work out like u planned at least u can live in peace with urself for trying. Some people have no consideration for the parents involved in situations like this. They think once its done its done & I think that all adoptive parents should at least try. It makes the biological parents feel more at ease that thier decision wasn't careless. Bless u for being considerate & wanting to make contact.