The advent of sperm sorting opens up the possibility that sex selection could become much more easily accessible, raising many moral questions. Two fundamental issues are whether sex selection is necessarily sexist and whether it should be highly regulated or banned on those grounds. I argue that, in some societies, sex selection of males is clearly sexist and that it promotes and reinforces extreme sexism. Extreme sexism seriously harms women, and if, in the opinion of those who know the situation best, prohibition is the best strategy for protecting women, a ban can be reasonable. In other societies, there may not be a pronounced preference for males, and sex selection may be neither particularly harmful nor even sexist. In those cases, there is no obvious benefit from prohibition, and prohibition may even represent a risk to women's reproductive autonomy.