"x x x.
In order to remove any confusion that may be engendered by the foregoing cases, we hereby set the following guidelines in appreciating age, either as an element of the crime or as a qualifying circumstance.
1. The best evidence to prove the age of the offended party is an original or certified true copy of the certificate of live birth of such party.
2. In the absence of a certificate of live birth, similar authentic documents such as baptismal certificate and school records which show the date of birth of the victim would suffice to prove age.
3. If the certificate of live birth or authentic document is shown to have been lost or destroyed or otherwise unavailable, the testimony, if clear and credible, of the victim’s mother or a member of the family either by affinity or consanguinity who is qualified to testify on matters respecting pedigree such as the exact age or date of birth of the offended party pursuant to Section 40, Rule 130 of the Rules on Evidence shall be sufficient under the following circumstances:
a. If the victim is alleged to be below 3 years of age and what is sought to be proved is that she is less than 7 years old;
b. If the victim is alleged to be below 7 years of age and what is sought to be proved is that she is less than 12 years old;
c. If the victim is alleged to be below 12 years of age and what is sought to be proved is that she is less than 18 years old.
4. In the absence of a certificate of live birth, authentic document, or the testimony of the victim’s mother or relatives concerning the victim’s age, the complainant’s testimony will suffice provided that it is expressly and clearly admitted by the accused.
5. It is the prosecution that has the burden of proving the age of the offended party. The failure of the accused to object to the testimonial evidence regarding age shall not be taken against him.
6. The trial court should always make a categorical finding as to the age of the victim.
x x x."