Well, here's some news.
A Los Angeles study suggested that four consecutive years of having a teacher from the top 25 percent of the pool would erase the black-white testing gap. — Nicholas Kristof in the NYT
PS: Remember then-Harvard President Lawrence Summers' speculations on whether biological differences between men and women resulted in women being at a disadvantage in mathematics, and that explained the relative absence of women in certain sciences? Well, funnily, it turns out that this so-called math gap doesn't exist in societies with high gender equality. See this.
The researchers also studied the percentage of students of each sex among the top scorers on the test. In the gender-equal countries, girls made up half or more of those who scored in the top one percent. The sex ratio of top performers is especially important because these students are the ones most likely to excel in careers in science and engineering. Summers had suggested that because of biological differences, it is nearly inevitable that a much higher percentage of these top performers will be boys.A difference does persist - girls do better at arithmetic than geometry; boys do better at geometry.
My takeaway is that biological differences may be real; but we are currently no where near being able to attribute persistent inequality to those differences - cultural or environmental factors are currently much more important. The tendency of the conservative is to try to justify the status quo as both correct and immutable, at one time as God-given, and now as determined by genetics and biology.
