At the elite college I attended, there were lots of male Chinese math professors, but I do not recall any female ones. If the right-tail effect is not present in the Chinese, for example, where are the great female Chinese mathematicians? Similarly, I can think of many more great Russian male mathematicians than female ones. Can you name a country where there are as many top-notch female mathematicians as male ones?
Bostonian, did you read the open-access article I linked? As to why there are fewer female mathematicians, while it's possible genetic difference plays some slight role, there are of course MANY other better explanations. As is explained in several of these articles, even if we look purely at raw data among those who are highly talented, the ratios we see (3 or maybe 4 to 1 M:F, at present) do not represent the actual ratios of men to women in the field. Obviously, something else is at work.
