Complex behavioral patterns in animals are the result of concerted actions of multiple genes functioning in the context of internal and external environmental cues. Many researchers have attempted to correlate specific loci in humans with behaviors, but the complexity of genetic and environmental interactions, as well as the pleiotropic effects of these genes, make it difficult to definitively map loci associated with behaviors. Use of genetically tractable model systems such as Drosophila has enabled researchers to identify behavioral genes and begin characterization of the signal transduction pathways in which they reside. One well-studied behavior in Drosophila is courtship behavior in which specific actions and reactions are associated with each of the sexes. Alterations in two Drosophila genes, fruitless (fru) and dissatisfaction (dsf), result in aberrant male (fru) or male and female (dsf) courtship, causing sterility. The goal of this research is to isolate additional loci required for sex-specific mating behaviors in an effort to link these genes to nervous system outputs. The first approach relies upon over-expression of unknown genes to rescue sterility associated with dsf or fru. The second approach is analysis of previously identified male-sterile alleles. Understanding of sex-specific functions of genes identified in this study will provide insights into neuronal function in higher taxonomic groups.