You must be 18 with a valid state or governement issued photo ID to be pierced without parent's or guardian's consent.
Parents or guardians may sign for but must be present for a minor's piercing.
For any piercing of a minor, a parent or legal guardian must be present to sign a consent form. Proof positive, state or government issued photo identification is required from the legal guardian, and a bona fide form of identification from the minor.
Under no circumstances is it acceptable or appropriate for a piercer to perform piercing on the nipples or genitals of an individual under 18 years of age.
A.D.I.'s minimum age for navel piercing is 14. Minimum age for tongue piercing etc. is 15