Whether there is a mens rea requirement for Scienter in 18 U.S.C. Section 2251

QUESTION(S) PRESENTED ; Is there a mens rea requirement for Scienter in 18 U.S.C. Section 2251, since "_.. criminal responsibility may not be imposed without some element of Scienter on the part of the Defendant"? quoting: SMITH v CALIFORNIA, 361 US 147 (1959) . HAMLING v UNITED STATES, 418 US 37 (1974) OSBORNE v. OHIO, 495 US 103 (1990) BUILDING & CONST. TRADES COUNCIL, 485 US 568 (1988)