My 13 year old daughter's birth parents have contacted her

Did you adopt? Was it a closed adoption? Did they contact you first? Did you tell your daughter she was adopted before this happened?

ANY question on law needs to include your general locale as laws vary by area.

Finally, what is your question?

I would hope if they have had no contact that they contracted you first of course.
And if it was a closed adoption, they have no legal right to, and no right to without talking to you first.

Was it open or closed adoption?
Did she know she was adopted ?

What did they contact for ?
Has this upset her?