In People v. Falsetta (1999) 21 Cal.4th 903, the California Supreme Court rejected federal due process challenges to Evidence Code section 1108 and that this court is obligated to follow the rulings of the California Supreme Court. (Auto Equity Sales, Inc. v. Superior Court (1962) 57 Cal.2d 450, 455.) In Falsetta, our Supreme Court found that the introduction of evidence of a defendant's commission of a prior sexual offense in a current prosecution does not violate due process because strict limitations are placed on the introduction of such evidence, including the trial court's balancing of its probative value and prejudice. (Falsetta, at pp. 917-920.) The Falsetta court cited with approval People v. Fitch (1997) 55 Cal.App.4th 172, 184, which rejected an equal protection challenge to Evidence Code section 1108 on the basis that it treats those accused of sex offenses differently from those accused of other crimes. The Fitch court held that Evidence Code section 1108, which creates two classifications of accused or convicted defendants, is subject to rational basis scrutiny. (Ibid.) The court concluded that Evidence Code section 1108 is supported by a rational basis because "the Legislature determined that the nature of sex offenses, both their seriousness and their secretive commission which results in trials that are primarily credibility contests, justified the admission of relevant evidence of a defendant's commission of other sex offenses." (Ibid.) While the Falsetta court announced no specific ruling concerning equal protection, the court noted that the Fitch court had rejected an equal protection challenge to the statute and quoted language from the Fitch decision's equal protection analysis. (Falsetta, supra, 21 Cal.4th at p. 918.)