Wait, you're basing this on the results of this one competition? (Also, with many of those names I can't tell if they are male or female.) I don't think this is a good idea. Competitions are self-selecting, based on all kinds of things. At DD's gifted school, the math team is overwhelmingly male, but I can tell you right now that the top math students in her class (DD is not one) are about 60/40 male/female...not that significant of a split.
Chess has a similar problem. Girls may show promise in chess, but when they see that chess club is 3/4 male, or more, they tend to drop out, especially at older ages. You see younger girls try it, but they don't stay in.
With this said, there is also research showing that moms talk to male toddlers more about math and numbers, and they also give them more blocks and building toys. These early experiences have been shown to matter.
