The significance of small RNAs has profoundly touched the fields of development and physiology, human disease, and therapeutic treatment. Errors in small RNA functions are suspected to lie behind several diseases, including Fragile X Syndrome, DiGeorge Syndrome, and possibly certain Cancers. Small RNAs have been exploited by biotechnology companies and academic science to carry out reverse-genetic experiments. In the field of medicine, small RNAs have been shown to block HIV, polio, and hepatitis viral replication in cells and animals, block growth of cultured tumor cells, and lower cholesterol in lab animals. The therapeutic potential for small RNAs is enormous.