RonB, I'm not entirely clear on what stage you're at in the process of obtaining a birth certificate for your child.
410 ILCS 535/14 prescribes the method for obtaining that certificate.
410 ILCS 535/15 takes effect when the state office refuses your application for such record; however, it seems to me that you're still in the initial phase of your attempt to gain a birth certificate but are referring to Chapter 15 procedures. To clear things up, have you already applied for a Delayed Record of Birth from the IL Registrar of Vital Records, and been refused such record?
For the record, the parent is the "petitioner" in these matters when the record sought is for a minor:
(c) When the birth occurred more than 7 years prior to the application for registration, the certificate of birth shall be prepared on a form entitled "Delayed Record of Birth". The information provided on such registration form shall be subscribed and sworn to by the person whose birth is to be registered before an official authorized to administer oaths. When such person is not of legal age or is otherwise not competent to swear to this information, it shall be subscribed and sworn to by a parent, legal guardian, or other legally designated representative of this person.