(a) Any person applying for the license to marry another may introduce the parent or guardian of himself or herself or the other party, or the certificate of the parent or guardian duly attested, to prove to the satisfaction of the clerk that the parties to the marriage are of lawful age.
(b) In case either or both of the parties to the marriage are not of lawful age, it shall be the duty of the clerk, before issuing the license, to require the party applying therefor to produce satisfactory evidence of the consent and willingness of the parent or guardian of the party to the marriage, which shall consist of either verbal or written consent thereto.
(c) If there are any doubts in the mind of the clerk as to the evidence of the consent and willingness of the parent or guardian of the party applying for the license or if the clerk is in doubt as to the true age of the party so making application, the clerk may require the applicants to furnish a copy of their birth certificates as proof of lawful age or may require the parties to make affidavit to the genuineness of the consent granted or to the correctness of the ages given. The affidavit so made shall be filed in the clerk's office for public inspection.