The current goal of evidence-based medicine, prospective therapeutic interventions in large numbers of patients, may not always reach an accurate conclusion. Individual variations in genetic characteristics need to be acknowledged and taken into account in the analysis. Some women with recurrent vulvo-vaginal candiosis (RVVC) have polymorphisms in genes that directly contribute to their increased susceptibility to these infections. Similarly, genetic polymorphism analyses of mother and fetus, along with highly sensitive non-culture methods of microbial detection, have identified patients at elevated risk for premature labor and delivery. Utilization of more complete information provides the basis for more specific and individualized therapeutic interventions.