Post-adoption visitation rights for the natural grandparents of the adoptee may be granted when the adoptee is adopted by a stepparent, a grandfather, a grandmother, a brother, a half-brother, a sister, a half-sister, an aunt or an uncle and their respective spouses, if any. Such visitation rights may be maintained or granted at the discretion of the court at any time prior to or after the final order of adoption is entered upon petition by the natural grandparents, if it is in the best interest of the child.