Iowa Admin. Code r. 441-99.27
The alleged father may contest the paternity establishment by submitting, within 20 calendar days after service of the notice upon him, as provided in rule 441-99.23 (252F), a written statement contesting paternity to the address of the unit as set forth in the notice. The mother may contest paternity establishment by submitting, within 20 calendar days after the unit mailed her notice of the action or within 20 calendar days after the alleged father is served with the original notice, whichever is later, a written statement contesting paternity to the address of the unit as set forth in the notice. When paternity is contested, or at the unit's initiative, the unit shall issue ex parte administrative orders requiring the alleged father, the mother and the child to submit to paternity testing. If the mother and child or children previously submitted blood or genetic specimens in a prior action to establish paternity against a different alleged father, the previously submitted specimens and prior results, if available, may be used for testing in this action.
Iowa Admin. Code r. 441-99.27