Section 2423(a) of Title 18 prohibits anyone from transporting any individual under the age of 18 years in interstate or foreign commerce with the intent that the minor engage in prostitution or any criminal sexual activity. It imposes a maximum 15 years' imprisonment and/or a fine under Title 18.
Section 2423(b) prohibits anyone from traveling, or conspiring to do so, in interstate or foreign commerce for the purpose of engaging in any sexual act, as defined in Section 2246, with a person under 18 that would be a violation of chapter 109A if the sexual act occurred in the special maritime and territorial jurisdiction of the United States. The penalty under this section is imprisonment for a maximum of 15 years and/or a fine.
Note that Section 2423(b) has been used in prosecutions for interstate travel with the intent to have sex with minors, some of whom were contacted through computer on-line services. Moreover, Section 2423(b) should be used for international sex tourism cases as well.
[updated April 2000] [cited in USAM 9-75.300]