Who writes Wikipedia articles? Young men.
Only 13% of Wikipedia Contributors Are Women, Study Says - Digits - WSJ

The November survey, which had some 175,000 valid responses, was conducted in multiple languages by the Wikimedia Foundation, the nonprofit that operates the site, and United Nations University’s tech-research program MERIT. They presented the initial findings last week at Wikimania, an annual conference held this year in Buenos Aires. A comprehensive report is scheduled for November.
Of the 53,888 respondents who said they contribute to Wikipedia, only 6,814 were women. The male/female ratio is closer among those who read entries but don’t write or edit them: 69% men to 31% women.
The average respondent age hovers in the twentysomethings. Men tend to be a few years older, at 26, while women were 24 on average.
Altruism and fact-checking are the top motivations of contributors, the study found. About 73% indicated “I like the idea of sharing knowledge and want to contribute to it,” while 69% said “I saw an error I wanted to fix.”