I have wondered if some non-Asian children and girls notice that the math club (or the local chess club) is mostly Asian and male and decide that it therefore not for them. But then it is their own biases that are at fault.
I think it is naive to attribute the bias *solely* to the kids vs. the environment they experience up to the point of making the decision to participate or not.
That said, my strong-willed DD *refused* to participate in MathCounts throughout middle school, despite personal invitations from the teacher who mentored the school team (and who is also the coach of the state team, which generally does quite well in national competition). I have no regrets about that, and was glad she had the time for other activities. She does not need the competition to motivate her - she has just finished Calc AB as a high school freshman, with a deeper understanding of the concepts covered in that course than most of the engineering undergraduates I teach.
