As Fine argues in this forceful, funny new book, the notion that gender accounts for differences in minds and behavior through some biological, brain-based process is an idea as popular as it is unproven. Promoted by popular science and pop psychology authors, nudged along by credulous newspaper and magazine editors looking for hot headlines, a cottage industry has emerged to convince us that men and women are, metaphorically at least, from other planets. These ideas — that boys and men are naturally better at understanding systems and things, while girls and women tend toward skills with people and emotions — are nothing novel. “As an empirical endeavor,” Fine points out, “the neuroscience of sex differences began in earnest in the mid-nineteenth century,” when their findings were used to oppose women’s suffrage and equal rights in general. Still, it’s notable how these ideas have been resurrected, after a period in which gender differences, and sexism itself, were mostly seen as having historical, societal, and cultural roots. Nowadays, when we find ourselves in a society in which women still can’t quite have it all, it’s no surprise that old notions are making a comeback, with an assist from advanced brain imaging — used, as Fine says, “to reinforce, with all the authority of science, old-fashioned stereotypes and roles.”