To be useful in identification, the genetic marker must be stable over an individual's lifespan, frequencies of the various genetic types in relevant populations must be known, and the marker must be stable in the evidence material investigated. The test materials and methods must be accessible and sensitive, and must include well-defined typing standards and test controls. The ABO blood group system provides markers useful in paternity testing. Recent advances in technology have now made it possible to detect genetic variation directly at the dioxyribonucleic acid (DNA) level. In 1985, a new group of DNA polymorphisms was discovered that appears as a complex array of bands similar to supermarket bar codes. Each individual appears to have a unique code. Advances in sequencing technology offer the promise of decoding these DNA sequences from very small amounts of material. This new technology appears to fit most of the requirements needed to be useful in identification.