U.S.C. Title 18 - Crimes and Criminal Procedure Part I - Crimes Chapter 109A - Sexual Abuse.

Section 2241. Aggravated sexual abuse (1/5/99)

(a) By Force or Threat. - Whoever, in the special maritime and territorial jurisdiction of the United States or in a Federal prison, knowingly causes another person to engage in a sexual act -
(1) by using force against that other person; or
(2) by threatening or placing that other person in fear that any person will be subjected to death, serious bodily injury, or kidnapping; or attempts to do so, shall be fined under this title, imprisoned for any term of years or life, or both.

(b) By Other Means. - Whoever, in the special maritime and territorial jurisdiction of the United States or in a Federal prison, knowingly -
(1) renders another person unconscious and thereby engages in a sexual act with that other person; or
(2) administers to another person by force or threat of force, or without the knowledge or permission of that person, a drug, intoxicant, or other similar substance and thereby -
(A) substantially impairs the ability of that other person to appraise or control conduct; and
(B) engages in a sexual act with that other person; or attempts to do so, shall be fined under this title, imprisoned for any term of years or life, or both.

(c) With Children. - Whoever 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 special maritime and territorial jurisdiction of the United States or in a Federal prison, knowingly engages in a sexual act with another person who has not attained the age of 12 years, or knowingly engages in a sexual act under the circumstances described in subsections (a) and (b) with another person who has attained the age of 12 years but has not attained the age of 16 years (and is at least 4 years younger than the person so engaging), or attempts to do so, shall be fined under this title, imprisoned for any term of years or life, or both. If the defendant has previously been convicted of another Federal offense under this subsection, or of a State offense that would have been an offense under either such provision had the offense occurred in a Federal prison, unless the death penalty is imposed, the defendant shall be sentenced to life in prison.

(d) State of Mind Proof Requirement. - In a prosecution under subsection (c) of this section, the Government need not prove that the defendant knew that the other person engaging in the sexual act had not attained the age of 12 years.