Who determines the number of genders- and how?

As I understand it there are 39 genders, but the number may in fact be in the thousands. By what scientific rubric is the philosophy of infinite genders achieved? 39 genders seems a bit high, but I have been told there could be so to 10,000 ( and if I dont agree I'm apparently a 'bigoted cis white male'). Okay if there are many genders , how is this determined?

via International Skeptics Forum https://ift.tt/2Hly9pv