After he saw a New York Times article on the gender gap among Wikipedia contributors (The contributor base is only 13 percent women), Santiago Ortiz plotted articles by number of men versus number of women who edited. It's interactive, so you can mouse over dots to see what article each represents, and you can zoom in for closer look in the bottom left.
At first glance, the difference doesn't look that big, but notice the values of the axes. The axis for men on the horizontal is from 0 to 200, the axis for women is 0 to 20, and the equal ratio line is the purple one that's nearly vertical. So the only article with more women contributors is on cloth menstrual pads.
See also: what the chart looks like with equally-spaced increments. The results are clear.