All adoptees have two sets of parents.
I believe they have the right to know both sets of parents. The relationships will not be quite the same for each but those relationships should exist. Help them to understand that you want to know where you came from, who you look like, where you got a special talent or strange oddity in your personality. Your medical information, though maybe not important to you now, will be in the future when you have children. Adoptees who are now parents can attest to this.