Tex. Code of Criminal Procedure § 38.372

(a) In this article, "victim" includes the victim of an extraneous offense or act with respect to which evidence is introduced during the prosecution of an offense described by Subsection (b).

(b) This article applies to a proceeding in the prosecution of a defendant for an offense, or for an attempt or conspiracy to commit an offense, under any of the following provisions of the Penal Code:

(1) Section 20A.02(a)(3), (4), (7), or (8) (Trafficking of Persons);

(2) Section 20A.03 (Continuous Trafficking of Persons), if the offense is based partly or wholly on conduct that constitutes an offense under Section 20A.02(a)(3), (4), (7), or (8);

(3) Section 21.02 (Continuous Sexual Abuse of Young Child or Disabled Individual);

(4) Section 21.11 (Indecency with a Child);

(5) Section 22.011 (Sexual Assault);

(6) Section 22.012 (Indecent Assault); or

(7) Section 22.021 (Aggravated Sexual Assault).

(c) In the prosecution of an offense described by Subsection (b), reputation or opinion evidence of a victim's past sexual behavior is not admissible.

(d) Except as provided by Subsection (e), in the prosecution of an offense described by Subsection (b), evidence of a specific instance of a victim's past sexual behavior is not admissible.

(e) A defendant may not offer evidence of a specific instance of a victim's past sexual behavior unless the court:

(1) on a motion by the defendant made outside the presence of the jury, conducts an in camera examination of the evidence in the presence of the court reporter; and

(2) determines that the probative value of the evidence outweighs the danger of unfair prejudice to the victim and that the evidence:

(A) is necessary to rebut or explain scientific or medical evidence offered by the attorney representing the state;

(B) concerns past sexual behavior with the defendant and is offered by the defendant to prove consent, if the lack of consent is an element of the offense;

(C) relates to the victim's motive or bias;

(D) is admissible under Rule 609, Texas Rules of Evidence; or

(E) is constitutionally required to be admitted.

(f) The court shall seal the record of the in camera examination conducted under Subsection (e)(1) and preserve the examination record as part of the record in the case.