Any of the following adults may adopt:
   I. Husband and wife together.
   II. An unmarried adult.
   III. The unmarried parent of the adoptee.
   IV. A married person without that person's spouse joining as a petitioner, if the adoptee is not the petitioner's spouse; and if any one of the following circumstances apply:
      (a) The petitioner's spouse is a parent of the adoptee and assents to the adoption;
      (b) The petitioner and his or her spouse are legally separated;
      (c) The failure of the petitioner's spouse to join in the petition is excused by the court by reason of prolonged unexplained absence, unavailability, or circumstances constituting an unreasonable withholding of assent; or
      (d) The petitioner's spouse assents to the adoption and the adoptee is over the age of 18.
Source. 2004, 255:1, eff. Jan. 2, 2005.