An emerging problem of some interest is whether we can determine the population membership of a single individual, using a population-specific "genetic fingerprint." The levels of accuracy and precision required are beyond the reach of allozyme analysis, and attention has shifted to DNA polymorphisms. There are different types of DNA markers available for population surveys: RFLPs, mini- and micro-satellites, and RAPDs, and each type has its own strengths and weaknesses. We present a generic analysis that relates gene pool separation to our ability to assign individuals, an analysis that does not depend on the type of marker. We then review strengths and weaknesses of different DNA markers, in the context of DNA fingerprinting. Codominant loci are best. It is possible to gain more information per marker with multiallelic loci, but diminishing returns set in rapidly, and it is better to add loci. A modest number of independent loci is best, each locus with a modest number of alleles and with each allele in modest frequency.