The subject invention pertains to biomarkers for detecting vaginal epithelial cells in a sample, particularly, a forensic sample. In one embodiment, the level of methylation at the PFN3A locus in the genetic material isolated from the sample is used to detect and/or quantify vaginal epithelial cells in a sample. In another embodiment, the level of methylation at the PFN3A locus in the genetic material isolated from a sample is determined by pyrosequencing technique using specific primers described herein. A further embodiment of the invention provides a method of determining the level of methylation at the PFN3A locus in the genetic material isolated from a cell suspected of being a vaginal epithelial cell and that is isolated from a sample. Kits containing primers and reagents for carrying out the methods disclosed herein are also provided.