Whoever, in the special maritime and territorial jurisdiction of the United States or in a Federal prison, or in any prison, institution, or facility in which persons are held in custody by direction of or pursuant to a contract or agreement with the head of any Federal department or agency, knowingly engages in a sexual act with another person who—

(1) has attained the age of 12 years but has not attained the age of 16 years; and

(2) is at least four years younger than the person so engaging;

Whoever, in the special maritime and territorial jurisdiction of the United States or in a Federal prison, or in any prison, institution, or facility in which persons are held in custody by direction of or pursuant to a contract or agreement with the head of any Federal department or agency, knowingly engages in a sexual act with another person who is—

(1) in official detention; and

(2) under the custodial, supervisory, or disciplinary authority of the person so engaging;

In a prosecution under subsection (a) of this section, it is a defense, which the defendant must establish by a preponderance of the evidence, that the defendant reasonably believed that the other person had attained the age of 16 years.

(1) In a prosecution under subsection (a) of this section, it is a defense, which the defendant must establish by a preponderance of the evidence, that the defendant reasonably believed that the other person had attained the age of 16 years.

(2) In a prosecution under this section, it is a defense, which the defendant must establish by a preponderance of the evidence, that the persons engaging in the sexual act were at that time married to each other.

In a prosecution under subsection (a) of this section, the Government need not prove that the defendant knew—

(1) the age of the other person engaging in the sexual act; or

(2) that the requisite age difference existed between the persons so engaging.

(Added Pub. L. 99–646, § 87(b), Nov. 10, 1986, 100 Stat. 3621, and Pub. L. 99–654, § 2, Nov. 14, 1986, 100 Stat. 3661; amended Pub. L. 101–647, title III, § 322, Nov. 29, 1990, 104 Stat. 4818; Pub. L. 104–208, div. A, title I, § 101(a) [title I, § 121[7(c)]], Sept. 30, 1996, 110 Stat. 3009, 3009–26, 3009–31; Pub. L. 105–314, title III, § 301(b), Oct. 30, 1998, 112 Stat. 2979; Pub. L. 109–162, title XI, § 1177(a)(4), (b)(1), Jan. 5, 2006, 119 Stat. 3125; Pub. L. 109–248, title II, § 207, July 27, 2006, 120 Stat. 615; Pub. L. 110–161, div. E, title V, § 554, Dec. 26, 2007, 121 Stat. 2082.)