Simply discriminating by sex doesn’t identify those groups.
Quite agree. To me as a sociologist , sex is not a very useful variable either.Obviously most of you, with a small but discrete few exceptions, are biologically ascribed to one sex or the other. Intersex as a category is an issue I’ve raised before, not for its explanatory value, but simply to demonstrate in those few cases, that one either argues as a positivist for an abnormal category, or sees the phenomena as demonstrating genetic separation is not absolute …but lets not get into arguments on black swans!
More importantly is the fact that in social world a conception of gender , which involves both ideological context , social and self ascription, is more appropriate in an educational setting . However this is not a useful dividing tool , except to the extent that is a quick and dirty measure which helps admittedly some of the people some of the time.