662 ASHCROFT v. AMERICAN CIVIL LIBERTIES UNION Opinion of the Court exhibition of the genitals or post-pubescent female breast; and "(C) taken as a whole, lacks serious literary, artistic, political, or scientific value for minors." §231(e)(6). "Minor[s]" are defined as "any person under 17 years of age." §231(e)(7). A person acts for "commercial purposes only if such person is engaged in the business of making such communications." "Engaged in the business," in turn, "means that the person who makes a communication, or offers to make a communication, by means of the World Wide Web, that includes any material that is harmful to minors, devotes time, attention, or labor to such activities, as a regular course of such person's trade or business, with the objective of earning a profit as a result of such activities (although it is not necessary that the person make a profit or that the making or offering to make such communications be the person's sole or principal business or source of income)." §231(e)(2). While the statute labels all speech that falls within these definitions as criminal speech, it also provides an affirmative defense to those who employ specified means to prevent minors from gaining access to the prohibited materials on their Web site. A person may escape conviction under the statute by demonstrating that he "has restricted access by minors to material that is harmful to minors"(A) by requiring use of a credit card, debit account, adult-access code, or adult personal identification number; "(B) by accepting a digital certificate that verifies age; or '(C) by any other reasonable measures that are feasible under available technology." § 231(c)(1).