People who object to the by-product hypothesis [for female orgasm] are doing something strange: They're saying that it's hugely important to them tha… - Steve Stewart-Williams

As a result of cumulative culture, we have ideas in our heads that are orders of magnitude smarter than we are.

This is especially important when addressing less statistically savvy audiences. Such audiences could perhaps be encouraged to think of two normal distributions, one representing males and the other females. Instead of imagining that natural selection creates two distinct psychological types — a male type and a female type, described by the mean values for each group — they could be encouraged to imagine that natural selection pushes the male and female distributions closer together or further apart. This simple expedient may help people to visualize the effects of natural selection on average sex differences without at the same time losing sight of the variation within each sex.

A well-designed parental male will tend to end up investing in his own offspring, rather than the offspring of his good-looking next- door neighbor. And one way to help ensure that this happens is to be easily moved to jealousy.