Start with the good: Prof Rippon succeeds in challenging many common beliefs regarding sex-based differences in our brains. In my experience, the most common arguments people make to suggest that different outcomes between men and women are routed in biology refer to the following three 'facts' that Rippon addresses:
- Men show more variability in their abilities, so that even though men and women have roughly the same IQ on average, there are more male geniuses (and idiots). Rippon claims follow up studies have found this to not be the case.
- Girls with conditions such as CAH seem to have more 'male' preferences. Rippon quotes studies that suggest such girls do not have innately different preferences to other girls, but are instead less susceptible to stereotypes, which is why they develop exhibiting this behaviour (of course, being by nature more or less susceptible to stereotypes is also an innate factor, so I am not sure why Rippon does not consider this in more detail; still, I suppose her point is that if there were no stereotypes, such girls wouldn't behave differently to non-CAH girls).
- Countries with higher gender equality also show higher gaps in stats such as percent of women in science etc. Rippon argues that even in countries with high gender equality scores, boys have higher self-confidence in their science ability than women, and this possibly explains the gap. I must say, this is not Rippon at her most convincing.
The book also discusses a range of interesting studies, which make for good reading.
However, in my view, the book overall is not particularly good. Rippon's line of argument reminds me of an old joke: a parent tells off their toddler for picking fights with other children in the playground. "Who, me?" responds the toddler. "First, I have never been to that playground. Second, when I go, I don't fight. Third, when I do, the other children start it". Similarly, Rippon's thesis goes something like this: "there isn't really such a thing as a binary sex. And if there is, there don't seem to be significant brain differences between the two sexes. And if such differences exist, they are just as likely the results of experience and stereotypes rather than biology".
While she cites studies supporting each of these assertions, and makes convincing cases for some of them (her argument that differences between men and women are due to confounders seems reasonable), it is impossible for me (a layman) to evaluate these studies. She criticises a lot of past studies for poor design, or small sample sizes, and mocks journalists and other pop-science authors, but ultimately, what it comes down to is her word against the word of those she criticises. So while the book is worth reading if you have only heard the 'differences between men and women are innate' side of the story just to get a balanced picture, you won't come away with a decisive answer having read it.
(That said, a lot of her criticism does seem bizarre or inconsistent: for instance, she mocks scientists making inferences from studies on animals, or dismisses early theories that assign specific actions to particular parts of the brain; yet as far as I know it's quite common to study animals to infer facts about humans, and she herself then talks about how parts of the brain activate when people process particular problems. In addition, some of her arguments seem disingenuous: for instance, she argues that even hormones are not clearly male- or female-only, as both sexes have all kinds of hormones, and as the levels of each hormone in an individual vary based on social context - all true, no doubt, but are the levels of each hormone the same between sexes? And, the fact that social context can influence hormone levels does not preclude there being a significant biological / innate element at play.)
Two final considerations: the first is something that Rippon touches on, but (understandably, given how sensitive the topic is, especially these days), she does not elaborate - that is, the concept of gender vs sex: if, as Rippon wants to argue, there is no innate difference between men's and women's brains, then what does 'gender' mean? She makes a vague comment about how 'debunking the myth of the male brain or the female brain should have implications for the transgender community which will hopefully be seen as positive' but she stops short of explaining what these implications are. The logical conclusion of her argument is that, if the only difference between men and women is their genitals or their chromosomes (and not even that, since she suggests that sex may be more of a spectrum), then it does not make sense to say things such as 'I feel like a woman', other than to ascribe to existing stereotypes of what it means to feel like a woman. I understand why Rippon does not want to open this discussion, yet this is the discussion to which her argument inevitably leads.
The second is that, ultimately, in my view, people conflate the discussion on whether differences between the sexes are innate or socially constructed, and the discussion on policy and sexism. But interesting while the former discussion may be, it should have no bearing on the latter: it doesn't matter if the fact that there are more male scientists is mainly due to innate preference, if there are still barriers to women in science; even if few women want to be scientists, but are discouraged, that's a problem in itself. Yes, maybe innate preferences explain most of the pay gap - but if there is a part of the pay gap that's attributed to sexism, then that's an issue. I think this is important to keep in mind.