I was thinking it would be interesting to have a poll asking people's gender. Then I realized that one option might be all that was needed.
btcex.com keep such statistics with the help of Yandex search engine:
For all time visited not more than 3 women.
Users by age:
(Russian word "лeт" means "years")
11 лeт и мeнee 0,4%
12 – 17 лeт 7,8%
18 – 24 лeт 16,0%
25 – 34 лeт 63,8%
35 – 44 лeт 12,0%
45 – 54 лeт 0,0%
55 лeт и cтapшe 0,0%