Seems it would be a lot easier to do something about gender disparity in organized events. But as far as cycling as a practical mode of transportation and an everyday, casual, and enjoyable activity that fits into people's lifestyles, perception of safety is probably the overriding factor. You don't see too many women out on their own late at night in most places. As much as we like to pay lip service to equality, women do receive a lot of unwanted attention. I suspect that the path to more women taking to practical bicycling is going to be a slow and winding one, paved by more men and a few adventurous women helping normalize it in society before it becomes safe enough and accepted enough for more women to join.