§ 263.25 Proof of age of child.
  Whenever  it  becomes  necessary  for  the purposes of this article to
determine whether a child who participated in a sexual  performance  was
under  [the  age of sixteen years] AN AGE SPECIFIED IN THIS ARTICLE, the
court or jury may make such  determination  by  any  of  the  following:
personal  inspection  of the child; inspection of a photograph or motion
picture which constituted the sexual performance; oral  testimony  by  a
witness  to the sexual performance as to the age of the child based upon
the child's appearance; expert medical testimony based upon the  appear-
ance  of  the  child  in  the  sexual  performance; and any other method
authorized by any applicable  provision  of  law  or  by  the  rules  of
evidence at common law.