Nope. There aren't any laws that allow/require visitation rights for biological grandparents at all. For example, if my sister and her husband divorced, and my sister got the kids, there are no laws that would let the paternal grandparents have visitation.
Some states have judiciaries that have granted grandparent visitation, but, in general, non-custodial visitation rights for anyone who isn't a legal parent or guardian are not protected.

 No,there are no laws for even birthmothers. Its all just a social agreement based on the needs of the child involved and the parents desire for relationship with a birthfamily. Technically only a birthmother has any right to the child and only for a short period of time before the adoption is finalized.