 In multi-host and multi-parasite coevolution, the Red Queen dynamics could affect what host and parasite types will become dominant or rare.Science writer Matt Ridley popularized the term in connection with sexual selection in his 1993 book "The Red Queen", in which he discussed the debate in theoretical biology over the adaptive benefit of sexual reproduction to those species in which it appears.The connection of the Red Queen to this debate arises from the fact that the traditionally accepted Vicar of Bray hypothesis only showed adaptive benefit at the level of the species or group, not at the level of the gene (although the protean "Vicar of Bray" adaptation is very useful to some species that belong to the lower levels of the food chain).By contrast, a Red-Queen-type thesis suggesting that organisms are running arms races with their parasites can explain the utility of sexual reproduction at the level of the gene by positing that the role of sex is to preserve genes that are currently disadvantageous, but that will become advantageous against the background of a likely future population of parasites.