To be clear, I think that the stated belief that there is higher male variance is possibly true. I think it has a good chance of being false, but that's not the

To be clear, I think that the stated belief that there is higher male variance is possibly true. I think it has a good chance of being false, but that's not the point. Statistically, for example, the male population has a greater chance of genetic disease and indeed lives shorter life; this is supposed to be in part because of the lack of two x-chromosomes, which, as a mosaic, both express themselves in the ordinary female body. What's emphatically not true is assuming a normal distribution -- specifically out to the tails. It's not even clear that the variance doesn't turn around at some point to have higher female variance at the top end of the curve. It is extremely easy to synthesize violations of a normal distribution of ability for female subjects -- there seems to be a powerful threshold effect that, in addition to cutting out large numbers of young women in certain cultures in mathematical competition, tends to preferentially spare the very top. If things were normally distributed, of those women that compete in mathematics competitions, almost none would make it to the very top of the competition, mathematically. That has been proven empirically false. Few scholars directly assert that the normal distribution is a perfect model for intelligence, but people seem to take the implications quite seriously. I'm pretty sure they're mistaken on that front.