Pinker (but actually Trivers) on the difference attitudes towards sex between males and females:

Trivers has worked out how all the prominent differences between males and females stem from the difference in the minimum size of their investment in offspring. Investment, remember, is anything a parent does that increases the chance of survival in an offspring while decreasing the parent’s ability to produce other viable offspring. The investment can be energy, nutrients, time, or risk. The female, by definition, begins with a bigger investment—the larger sex cell—and in most species commits herself to even more. The male contributes a puny package of genes and usually leaves it at that. Since every offspring requires one of each, the female’s contribution is the limiting step on how many offspring can be produced: at most, one offspring for each egg she creates and nurtures. Two cascades of consequences flow form this difference:

First, a single male can fertilize several females, which forces other males to go mateless. That sets up a competition among males for access to females. A male may beat up other males to prevent them from getting to a female, or compete for the resources necessary to mate, or court a female to get her to choose him. Males therefore vary in reproductive success. A winner can beget many offsprings, a loser will beget none.

Second, the reproductive success of males depends on how many females they mate with, but the reproductive success of females does not depend on how many males they mate with. That makes females more discriminating. Males woo females and mate with any female that lets them. Females scrutinize males and mate only with the best ones: the ones with the best genes, the ones most willing and able to feed and protect her offspring, or the ones that the other females tend to prefer.

Male competition and female choice are ubiquitous in the animal kingdom. Darwin called attention to these two spectacles, which he dubbed sexual selection, but was puzzled as to why it should be males that compete and females that choose, rather than the other way around. The theory of parental investment solves the puzzle. The greater-investing sex chooses, the lesser-investing sex competes. Relative investment, then, is the cause of sex differences. Everything else—testosterone, estrogen, penises, vaginas, Y chromosomes, X chromosomes—is secondary. […] In a few species, the whole animal reverse the initial difference in investment between egg and sperm, and in those cases females should compete and males should choose. Sure enough, these exceptions prove the rule. In some fishes, the male broods the young in a pouch. In some birds, the male sits on the egg and feeds the young. In those species, the females are aggressive and try to court the males, who select partners carefully.