while it has been stated by the legal counsel of the WTBTS , that it is not law in some states to report, it is against federal statutes.
Federal Statutes
Relating To
Crimes Against Children
The Federal Bureau of Investigation exercises jurisdiction and investigative responsibilities pursuant to the following federal statutes that pertain to various crimes against children. The following are summaries from the Federal Criminal Code and Rules under Title 18 of the United States Code (USC). Federal law defines a "minor" as a child under the age of eighteen unless specified otherwise.
Section 2241(a)(c). Aggravated Sexual Abuse
* Whoever, in the territorial jurisdiction of the Unites States or in a federal prison knowingly causes or attempts to cause another person to engage in a sexual act by using force against that other person, threatening or placing them in fear that another person will be subjected to death, serious bodily injury, or kidnapping.
Whoever knowingly crosses a state line with intent to engage in a sexual act with a person who has not attained the age of 12 years; or in the territorial jurisdiction of the Unites States or in a federal prison engages in a sexual act with a person who has not attained the age of 12 years; or whoever engages in a sexual activity by using force, threat, or other means described above, with an individual who has attained 12 years but has not attained 16 years of age.
Section 2243. Sexual Abuse of a Minor or Ward
* Whoever, in the territorial jurisdiction of the Unites States or in a federal prison knowingly engages in a sexual act (or attempts to do so) with another person who has attained the age of 12 years but not 16 years and is at least four years younger than the person so engaging.
http://www.fbi.gov/hq/cid/cac/federal.htm
just obey the law.