In this review, I stress the importance of incorporating Quantitative Genetics (QG) in the study of sexual selection through female mate choice. A short overview of QG principles and methods of estimating genetic variance and covariance is given. The state of knowledge is summarized as to two QG assumptions (genetic variance in female mating preferences and male sexual traits) and one QG prediction (genetic covariance between preferences and preferred traits) of models of sexual selection. A review is given of studies of repeatability of mating preferences because of recent accumulation of data. The general conclusion is that sexual traits and mating preferences show large genetic variation and are genetically correlated. The extensive genetic variation asks for an explanation that goes beyond the ususal explanations of the maintenance of genetic variation in fitness traits. Two models that explain the high genetic variance in sexual traits are treated in detail: modifier selection and condition dependence. There are many unexplored areas of QG research that could stimulate further research in sexual selection like the study of genetic covariance between mating preferences and good genes, of genetic variances and covariances of multiple male traits and multiple females preferences, of genetic variance in condition, and of condition dependence of mating preferences.