I'm not touching the variability thing with a 10 foot pole except to say that the further out on each extreme of the IQ "scale" you go the less reliable the scores are. The whole idea of using IQ as a ranking of ability rather than a diagnostic tools is bogus. I do think it's clear now though that Summers was simply being a misogynist (you lose the presumption of good faith when you disclose that you'd been lying all along.)