Good question. I assume that "relinquishment" refers to the termination of parental rights. Most states have cooperative adoption laws which, when appropriate and agreed upon, write post-adoption visitation into the adoption itself. If this is not the case, any visitation by the birth parents is up to you. There are advantages and disadvantages to post-adoption contact. I would strongly urge you, however, to spell out the details in writing. The frequency of visitation would depend on the nature of the relationship you have with the birth parents. Most such agreements are minimal. Perhaps an afternoon every one to three months, an afternoon during major holiday seasons, and the right to send a card or letter. In our experience, most birth parents request continued contact but do not follow through and the relationship fades and disappears.
Best wishes for a successful outcome. Jim Kenny, PhD