How is proof of age commonly verified?

Proof of age is commonly verified through a birth certificate because it is an official document that records an individual's date of birth and establishes their age at the time of birth. Birth certificates are typically issued by government authorities and are considered a reliable source for confirming age. They contain essential details such as the date of birth, name, and parents' names, making them a primary document for age verification in various legal and formal contexts, including insurance purposes.

While government-issued IDs also serve to prove age, they are not as definitive in confirming the exact date of birth as a birth certificate, which is the original source of this information. Witness statements are subjective and can vary in reliability, making them less useful for formal verification. A social security card, while associated with a person’s identity, does not provide definitive proof of age since it does not include the date of birth. Therefore, among the given options, the birth certificate is the most authoritative document for verifying proof of age.