Not to poke the bear or be a dick or anything but I also happen to believe that someone cannot change their gender (or sex or whatever you want to call it) from birth, does that mean I am ignorant and a jerk? I mean I wouldn't desciminate against anyone who was transgender or make fun of them but I'm never going to think of them as anything diffrent from what they were born as. All I'm saying is tolerance works both ways.
Although if people are making fun of transgender people then call them out all you want because they are being jerks.
sex is different then gender.
gender is what you identify as, and sex is what you were born with.
and how do you know than any woman you know, that you haven't seen carry a baby, isn't transgender and was a man once? it's not like all transwomen are 6'2" and have super broad shoulders.