What is the theme in The Red Queen: Sex and the Evolution of Human Nature by Matt Ridley?

Another theme is the battle of the sexes. According to the Red Queen hypothesis, many important human traits are the result of sexual selection. Sexual selection is the selection of traits because of their reproductive advantage. In a species like human beings, where the males compete for females, women have a huge control over which genes are selected for the next generation. If females prefer taller over shorter men, taller men will be more successful in reproduction and hence the trait for tallness will tend to be passed down. Males compete with other males for female approval and for reproductive advantage. Human males have developed "kamikaze" sperm that has no other purpose than to kill or immobilize the sperm of other males that may be competing with it inside the female.