Sex matters because it actually has implicit and unavoidable consequences. Men cannot get pregnant. But most of the things we apply to sex are arbitrary and obsolete. Thus, sex matters. Gender doesn't.
Nations and religions are arbitrary cultural constructions as are race and gender.

__________________
That information is classified and to be given only on a need-to-know basis...
And I do not need to know.

Get your daily dose of truth*

* or something approximating it