i'll ask a question i have my own opinion about; maybe it will open up an interesting dialog.
Sex vs Gender: to me there is a vast difference in these words, however close they may be in the english language.
sex is completely physical based (XX, XY, and all the various combinations).
as far as i'm concerned, there are 8 billion people on the planet therefore there are 8 billion genders.
My thoughts are that I agree completely with that statement. Sex is rather rigid as a term whereas gender is probably the most subjective word out there in the world today.