Section 12. Prohibition of Issuance of License. —

Upon compliance with all the legal requirements of sections seven, eight, nine, ten, eleven, and thirteen of this Act, the duty to issue the marriage license is ministerial. However, a marriage license shall not issue in case the municipal secretary or clerk of the Municipal Court of Manila, as the case may be, is convinced, in view of authentic documentary evidence in his possession, that the applicants —

1. Are related to each other in the degrees of relationship specified in section twenty-eight, or

2. Have not the legal age provided for in section two.