[az0xff]

Competing at the top level of any sport (athletic, mental, or otherwise) requires the right training and support almost as much as the right mindset, work ethic, and talent. The training and support requires time and money.

At present, people of different ethnicities have a disproportionate share of wealth, and thus fewer resources that they can spend on training and support. Support begins early: parents help their children find the right activity to undertake and also teach them the mentality to work hard at it in order to compete -- this is almost impossible to accomplish if those parents have to be away most of the time because of financial constraints.

As for gender, we have only recently entered an era where we recognize that girls are equally capable of doing things like math at a top level (the first Fields Medal given to a woman was given to them quite recently). In girls' formative years, parents still have some subconscious expectations of what their children are capable of -- perhaps being reluctant to expose girls to the sciences or other serious undertakings. There are some recent efforts to get girls into these things, but the fact that they are newsworthy proves that it's not the norm yet. The time that there will be equal female representation in these areas will be when an entire generation understands that women and girls are equally capable of getting into them. This will be after everyone who comes from the previous era of society have died.

[SamReidHughes]

Your theories would be plausible if the number of girls competing at a close-to-top level wasn't outnumbered by the number of boys who by any life-background metric would have no business being there. I'm talking about trailer park kids, poor immigrants, schizophrenics, and absolute slackers here. It will take some training and practice to get on an IMO team -- because your competition is doing so -- but at levels below that, girls are outnumbered by boys making no special effort in math that just show up and get high scores on contests.

Realize that anybody that would be at, say, top-500-high-school-students-in-USA math level will be the sort of student that coasts through all their math classes from K-12, with the typical schedule taking pre-calc in 10th grade, with no studying and no stress at all, easily the best in their class, assuming the school system just ignores their talents. There would have to be 250 girls in this situation, of which those that finish over the top 500 threshold on things like the AMC or AIME or earlier contests are outnumbered by boys with less "support" that just show up and get high scores on math contests.

Also, in my experience in middle school there were many girls that were quite competitive in 24 game, that just disappeared in more mathy contests like MathCOUNTS.