Probabilities and Human Pubic Hair Comparisons

Abstract

Abstract Often, when testifying in court, forensic scientists will state that an unknown substance is similar to a known source and that it could have originated from that source or from some other source with similar characteristics. When the substance in question is something like paint or fibers, the courts will have an intuitive feeling for the probabilities involved. However, with pubic hairs it is difficult for the courts to determine the weight to be placed on evidence concerning similarities. If a pubic hair from the scene of a crime is found to be similar to those from a known source, they do not know whether the chances that it could have originated from another source are one in two or one in a billion. In an attempt to provide a “ballpark” estimate of such probabilities, this study was begun.