The present study investigates factors mediating odor and social preferences in female house mice (Muc domesticus) based on the t-complex genotype of males. Previous studies in this laboratory showed that females prefer the odors of wild-type (+/+) males over those that carry lethal genes (+/t). The purpose of this study was to determine the genetic, hormonal, and environmental factors that regulate these preferences. The variables examined include t-complex genotype, genetic background, estrous condition of test females (+/+ or +/t), and genotype of the test female's parents. Results indicate that female preferences for +/+ males are dependent upon the t-complex genotype and estrous condition of test females. Only +/t females in estrus showed preferences for +/+ males. Estrous cycle condition effects were seen in both wild (+/+w5) and inbred (129 +/tw5)females. Homozygous females (+/+) and diestrous females of both genotypes did not demonstrate preferences for either +/+ or +/t males.