[O]ne of the strongest examples of essentialism concerns the difference between the sexes. Before ever learning about physiology, genetics, evolutionary theory, or any other science, children think that there is something internal and invisible that distinguishes boys from girls. This essentialism can be explicit, as when one girl explained why a boy will go fishing rather than put on makeup: “’Cause that’s they boy instinct.” And seven-year-olds tend to endorse statements such as “Boys have different things in their innards than girls” and “Because God made them that way” (a biological essence and a spiritual essence). Only later in development do children accept cultural explanations, such as “Because it is the way we have been brought up.” You need to be socialized to think about socialization.

Paul Bloom, How Pleasure Works: The New Science of Why We Like What We Like, New York, 2010, p. 17