Powers answer is pretty much what my answer was going to be had I not fallen asleep before I had the time to compose a full response.  I view invalidating someone else's gender identity as a pretty egregious violation of the safe space that this list should, ideally, be.  I say "gender identity" instead of "identity as a woman" because I intend the statement to apply to all genders; I'm not okay with someone invalidating someone's identity as a woman, someone's identity as a man, or any other gender identity someone on this list may have.  The context I would imagine this being most likely to come up in on this list is where someone's gender identity doesn't match their birth sex, but that's certainly not the only context I can see it being a problem in. If a situation comes up where someone is clearly attempting to invalidate someone's gender identity not out of ignorance or as a slip-up (heck, I've used the wrong pronoun for one of my housemates at least once this week,) but out of more sinister motives, then things are, in fact, likely to go BOOM.  But, as has been outlined in pretty much every discussion of the moderation of this list previously, no one needs to worry about being moderated for making a mistake, or for being unfamiliar with a concept.