Sorry, my language has only 1 word for sex and gender so for me it is the same and i don't understand the disscusions about it.

That is part of why I said it is completely understandable that people would be ignorant of the difference. But no matter what language/culture you're dealing with, trans people exist somewhere, and if a language cannot account for these people it kind of speaks toward the language's primitiveness and its refusal to evolve and get with the times.