Until recently, sex and gender meant the same thing
You are right, and you are wrong.
To scientists, sex and gender meant the same thing. I asked two of my sisters a few years ago and they both said sex and gender is interchangeable; they mean the same thing. Both of those sisters have degrees in Biology.
I was at a lecture on this subject about 5 years ago and there were several current biology students in the audience, including a Master's student who I spoke with. They assured the audience that sex and gender meant the same thing in all their course work.
But, non-scientific people started to use the word "gender" to mean something different. They call it a social construct. They say it not a black and white thing (you can be a mix of both genders). They talk about "gender roles". I think it started way back in the 1950's by feminists of the time. Most feminine traits would be associated with the "woman" gender and most masculin traits would be associated with the "man" gender. I think it started when women wanted to be respected for being able to perform some roles that were male dominated.
But, and this is important, it is
not important. It is like a theory that can never be proven or dis-proven. It is a concept and it
will always only be a concept. Arguing about it is pointless. It is a trap to argue about something that can never be proven or dis-proven.
It is a leftist tactic: Define a word, then argue about the meaning of the word.
Why?
Because it fools weak-minded people into believing that the definition of the word is way more meaningful than it is. Look at the people in this thread. They think
"Oh, I know what gender means. They do not understand what gender is. They think dudes with dicks should not be able to invade women's spaces. Therefore, dudes with dicks should be able to invade women's spaces."
Seriously. Read that again. That is exactly their rationale for fighting so hard for something they know, deep down they
know, is
wrong.