Thank you for concisely re-stating my major thoughts/issues. :) Specifically this: "Be careful if you don't have to go through training, because then some woman should have been desperate enough to use it before."

I feel like you don't have to go through training, but it would be really helpful. I'm toying with the idea that, over the years, since women weren't using magic and it was probably dangerous for women to use magic, some kind of sexual dimorphism regarding the use of magic rose up. As a result, men are generally more powerful magic users than women--because it hasn't been reproductively smart for women to be powerful magic users. Since women have generally less power than men, they would be less likely to stumble across it in an act of desperation (the desperation would have to be proportionately higher for a woman than for a man). Also, perhaps magic in women has been selected to be inconspicuous and unconscious--increasing one's lifespan, healing minor injuries at a quicker rate than a man, getting "feelings" about things that happen to be pretty decent warnings/predictors about the future, etc. Things that no one really sees as magic, because they're not consciously intended.

Okay. That turned out to be a really helpful comment. Thanks!