The amelogenin gene, which is located on human X and Y chromosomes, has been a central system to differentiate males from females in forensic casework and prenatal diagnosis. During the past several years, the Israel Defense Force (IDF) has been storing soldiers’ blood samples on FTA paper for purposes of DNA profiling. Distilled water had been used to purify the papers instead of the buffer recommended by the manufacturer. During the course of a quality control check of the bloodstain pool, a sample taken from a male soldier was genotyped as female and deoxyribonucleic acid profiling of a second sample from the soldier confirmed that sampling error had not occurred. The gender identification was conducted using both the AmpF/STR SGM plus and GenePrint kits. The soldier’s karyotype, however, was that of a normal male. As such, the authors conclude that out of a total of 96 samples, the failure rate of the amelogenin test is 1.04 percent in Israel. A mistyped amelogenin test has significant consequences in the forensic field. To reduce errors, other Y-locus STR’s should be routinely checked in sex crime cases to avoid incorrect conclusions. Figures, references