I have a firm belief that the clear lack of women in competitive programming is due not to their inferior brains, but rather to the vast male prevalence that makes them feel out of place.
Some efforts are being made to address this problem, eg Google Code Jam for Women, but in my opinion we are not there yet.
Thus I propose that codeforces, being the most prominent competitive programming platform, make some effort by establishing a weekly contest for women only, so that they may feel safe and not oppressed while coding.