If the mother declares in the Acknowledgment of Paternity form that there is a presumed father of the child, the acknowledgment must be accompanied by a Denial of Paternity form signed by the mother and the presumed father, unless the presumed father is the man who is acknowledging paternity. The Denial of Paternity is signed using the same procedures as the Acknowledgment of Paternity outlined in §55.404 of this title. The Acknowledgment of Paternity form and the Denial of Paternity form may be filed with the Texas Department of State Health Services, Vital Statistics Unit separately or simultaneously. If the acknowledgment and denial are both necessary, neither document is valid until both documents are filed.