The age of a person who participated in sexual conduct or a performance that contains a lewd exhibition of the genitals, anus, or breasts, or who was solicited for either by means designated under section 2828 of this title may be established by any method acceptable under the rules of evidence, including the following methods:
(1) inferences drawn by the trier of fact from inspection of a document that depicts sexual conduct;
(2) testimony as to the apparent age of the person by a witness to sexual conduct; or
(3) expert medical testimony based upon the appearance of the person depicted in a recording of sexual conduct.