"After sifting through near to three million pull requests submitted on GitHub, they found – against their expectations – that code written by women was approved at a slightly higher rate than that composed by men, 78.6 percent to 74.6 percent, respectively. That’s roughly an extra 120,000 pieces of code.
"Nevertheless, there was a depressing caveat: this rule only applied if their gender was unidentified. If female coders’ gender was known, their overall pull request acceptance rate fell from 78.6 percent to 62.5 percent. This appears to suggest that women may in fact be better coders, but are automatically discriminated against simply because of their gender."
Apart from that, there are endless examples of women being harassed, stalked, assaulted, and even killed because of their gender. Is it any wonder that many might prefer not to reveal their gender and enjoy the benefits of relative equality when they have the ability to do so, such as in an online forum like HN?
Really, you'd have to be living in a cave not to be aware of the existence of sexual harassment. Just on HN, articles about it float to the front page at least one or twice a month, which is why I really have to wonder if you are just trolling by asking that question.
[1] - http://www.iflscience.com/technology/women-are-seen-better-c...