The maintenance of genetic variance in fitness and the maintenance of sexual reproduction represent two mainstay evolutionary challenges that may, to some extent, have the same solution: sex-specific selection. Sex-specific selection inevitably leads to sexually antagonistic (SA) selection, which can maintain balanced polymorphisms for fitness (where alternative alleles pose opposite fitness effects in the two sexes). Alternatively, if/when the same alleles are favored in both sexes (i.e. sexually concordant (SC) selection) then sex-specific selection can account for the cost of sexual reproduction by enabling more efficient purifying selection via males at a negligible cost to population growth. At face value, these two processes seem at odds, but they likely act on largely independent sources of genetic variance, and therefore different loci in the genome. In order to fully understand how and why genetic variance and sexual reproduction are maintained so ubiquitously we need to study the mechanisms that enable the above processes to ensue. Current research foci are highlighted in the Research section. I study these and other questions using a broad range of techniques, including quantitative/statistical genetics, experimental evolution, genomics, transcriptomics, molecular genetics, and mathematical modeling.