The other book well worth reading is Lise Elliott's Pink Brain, Blue Brain (don't be put off by the title - it's about debunking the distinction). She's a neuroscientist whose area of expertise and research is brain plasticity in early childhood (if you can lay hands on a copy, her earlier book What's Going on in there: brain development from 0 to 5 is also superb - but sadly out of print).
In summary, she has a two-pronged attack on what Cordelia Fine calls neurosexism. First she goes through the literature on purported cognitive differences between the sexes and demonstrates that even in the few studies which are both methodologically robust and have statistically significant results, the differences they show up have tiny d-values (difference in means divided by product of standard deviations).
In the spirit of "a picture tells a thousand words" I've attached an image of d-values. Height (one of the more obviously dimorphic characteristics in humans) has a d-value of about 1.5 if memory serves me right; those few cognitive differences that have been measured come out with d-values below 0.5 - i.e. the distributions are almost indistinguishable. In real-world terms suppose, for instance, by 18 months the average girl has a vocab of 50 words and the average boy 45... however, it may well be that 48% of boys still outperform the average girl. So for instance to tell a mother with a son who is still non-verbal at 2.5 "don't worry, boys just talk later" is seriously misleading and even dangerous advice. (These are made up numbers btw, but ball-park correct - my copy is currently on loan to a friend).
The second prong is to point out that infant brains are incredibly plastic. Stimulate one aspect of their lives and that part of their brain will develop strongly; neglect to provide stimulus and it won't do so well. (NB, this is not "blank slate" - there are areas which are pre-primed, as it were, to develop in certain ways. Steven Pinker is very good on this in The Language Instinct. It's just that how well these pre-primed areas develop is determined to a larger degree than people realise by external stimuli.)
The other thing we know and can measure is that adults treat children of different sexes differently right from earliest infancy. (One study I read about looked at how adults treat newborns - girls are cuddled facing inwards and told they're beautiful, boys are often pointed outwards and given a running commentary on the world. One of the studies Elliott uses is 9 month babies and angled ramps - left to their own devices there's no difference in the steepness of ramps the babies can tackle, but mothers of daughters typically intervene and whisk their child to safety at a lower angle than mothers of sons.) All of this has a huge effect on the brain, so by the time researchers are carrying out experiments on cognitive difference (age of first words, rotational and spatial awareness puzzles, maths ability) there is no way you could devise an experiment that could separate out nature and nurture.
(And for the avoidance of doubt, yes I have read the whole book - it was fascinating and "un-put-downable". I've read the whole of The Language Instinct too - also a great read. I'm about half way through Fine at the moment.)