Pennsylvania Consolidated Statutes - Crimes and Offenses (Title 18) - Part II. Definition of Specific Offences.
Chapter 31- Sexual Offenses

Section 3107. Resistance not required

The alleged victim need not resist the actor in prosecutions under this chapter: Provided, however, That nothing in this section shall be construed to prohibit a defendant from introducing evidence that the alleged victim consented to the conduct in question.