Shoes that you think fit don't nessesarily- most cycling shoes are mighty narrow. I've got mens Chili pro's, got the numb feet, but got them stretched in the forefoot and the problem is 90% gone. Even lacing shoes too tight can be a problem. My orthotic guy has been educating me. Your feet swell through the first ten miles or so, so start loose.
Lake shoes are boxier in the toe and wider than usual. And they're leather, not plastic crap. I don't have long miles on them yet but am already a fan.
The female nerve impingement idea intrigues me. When you figure it out, please post!

missliz