In People v. Fitch (1997) 55 Cal. App. 4th 172, 184-185 [63 Cal. Rptr. 2d 753], the Court of Appeal upheld section 1108, the parallel statute permitting admission of prior sex offense evidence, against just such an equal protection challenge. The Fitch court first held that section 1108 does not infringe upon the cited constitutional rights to due process, fair trial, and conviction only upon proof beyond a reasonable doubt. The court then affirmed that an equal protection challenge to a criminal statute which, like section 1108, creates two classifications of accused or convicted defendants without implicating such a constitutional right, is subject to a rational-basis analysis. (Fitch, supra, at p. 184, citing Estelle v. Dorrough (1975) 420 U.S. 534, 537-538 [95 S. Ct. 1173, 1175-1176, 43 L. Ed. 2d 377].) The Fitch court concluded that section 1108 easily withstood "this relaxed scrutiny. "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. This reasoning provides a rational basis for the law. . . . In order to adopt a constitutionally sound statute, the Legislature need not extend it to all cases to which it might apply. The Legislature is free to address a problem one step at a time or even to apply the remedy to one area and neglect others. (People v. Silva (1994) 27 Cal. App. 4th 1160, 1170-1171 [33 Cal. Rptr. 2d 181].)" (Fitch, supra, 55 Cal. App. 4th at pp. 184-185.)