How many genders are there ?

Too many. Honestly, I dont think its worth even worrying about unless it affects my love life, my job, or my social life. Seeing as the whole gender identity thing is just too much energy into that, I dont care. There are males and females. Unfortunately your genitalia dictates so. If you wish to undergo sex reassignment surgery, then do it. But dont expect me to not mistaken you during your transition.

Basically, do what you want but bashing society over the head due to a small sliver of the population having identity issues is pretty over the top.