From
http://www.adultweblaw.com :
5. United States v Knox:
In Knox, a man who had previously been convicted of receiving child pornography through the mail ordered video tapes (by mail) of girls between the ages of ten and seventeen who, in the Court's words, "were dancing or gyrating in a fashion not natural for their age." The girls wore bikini bathing suits, leotards, or underwear - none of the girls in the videos was nude. The videos were set to music, and it appeared that someone off-camera was directing the girls. The photographer videotaped the girls dancing, and zoomed in on each girl's pubic area for an extended period of time. Knox was prosecuted under United States Child Pornography laws.
Legal counsel for Knox argued that "lascivious exhibition of the genitals or pubic area" meant that the girls had to be nude - wearing clothing meant that that genitals and pubic area were clearly not exhibited. The Court disagreed and held that there was no nudity requirement in the statute: "the statutory term "lascivious exhibition of the genitals or pubic area," as used in 18 U.S.C. § 2256(2)(E), does not contain any requirement that the child subject's genitals or pubic area be fully or partially exposed or discernible through his or her opaque clothing."
