Lets see what the jps community thinks.

Two, generally. However Klinefelter's, etc. are a thing. I guess we can agree on intersex as a rare third.

This.

OP: Your thread title references "sex", but your poll references "gender".

what exactly is new about this third sex?

Where exactly are you getting new from? the post you quoted says nothing of new.

3 Sexes if you count intersex as one
Gender has limitless possibilities

as long as you dont tell me what yours is, you can add it to the list of genders i dont care about.

i dont care if you're gay, straight, bi, or even into only wolf spirit pup play. stay away from my kids and have a personality that's something other than what gets you off and i wont bully you.

3 sexes if counting the rare born with both cases.

We are a bunch of numskulls... We don't count for much, we can't even get along in here!!!

100+ genders, i would say 1000 or even over 9000 easy.
2 sexes, have to be specified, since it seems a bit unclear / hardly reachable for some d2jsp userz.