_No_ mechanism? Seriously? How about when the user is named "Jane Smith"? Or, heaven forbid, they actually use a PROFILE PICTURE with their ACTUAL FACE. Oh god the horror!
I, as a white male with a caucasian sounding name have the privilege of being able to use my actual name on the internet. Women that want to be taken seriously don't even have that choice.
Sure over time women figure out that anonymizing their gender online is a wise strategy, but how many brand new programming-enthusiasts are going to learn this when they have negative first experiences on the most popular Q&A platform for programmers? How many never return to contribute because of those negative experiences?
It's no wonder you can't go to SO and find women, they either aren't contributing or they have effectively hidden themselves among the ranks of the men.