Whole genome amplification has been used as a powerful tool to increase the amount of DNA template used for microarrays, STR and SNP assays in clinical and forensic settings. Our laboratory observed that multiple displacement whole genome amplification demonstrated a higher reliability for increasing DNA template than PCR primer extension pre-amplification of human genomic DNA. We also demonstrated a truncated reaction time for whole genome amplification was necessary to decrease artifact, while still increasing authentic DNA species. We determined that molecular crowding using polyethylene glycol and non-human DNA also increased sensitivity of our assays. Combining the modified whole genome amplification protocol with macromolecular crowding increased STR signals with as low as one haploid cell DNA equivalent.