Moral philosophers argue that mechanisms such as reciprocal altruism and indirect reciprocity can result in the evolution of shared interests and a ‘moral sense’ in humans. This article discusses the need to broaden that view when considering the consequences of genetic conflict, in particular, the conflict associated with mate selection. An alternative application of evolutionary arguments to morality has been suggested by biologists such as Richard Alexander, who argue that ethical, moral and legal questions arise purely out of conflicts of (...) interest, and that moral systems (consisting of societal rules or laws) exist to ameliorate those conflicts. Following Alexander, a novel societal rule is proposed that could lessen the negative consequences to men of reproductive conflicts with women. (shrink)