Then I guess we are even.
To me, it makes no sense to reject the use of a word that has neutral connotations in favor of a word that has extremely heavy connotational baggage. (And yes, I am making up words here.)
Technically, MM, you are right.
Nevertheless, I also have been using “gender” dating back to a hideous conversation in the late 80’s concerning a research design I had with my graduate advisor and department head, also a bully and colossal A-hole. To my surprise, and without thinking, the word “gender” popped out of my mouth in reference to male/female data. He took the moment to repeat my phrase substituting “sex” for gender, letting me know what’s what in the most lascivious and “knowing” way. I’ve used the term “gender” ever since. Note that this was well before “gender” was in common usage. PS: I’m no shrinking violet.