Re: Work with facts
Not true. 1955. A generation before I was born, at least. 1970's, it was commonly-accepted terminology and knowledge. I wasn't even born for most of that. And gender is no more a choice than your sex, and no more clearly defined.
Plus it makes you sound like a twat.
And what you think is your biological sex has been known to be non-binary for a long time.
Biological sex is very much a combination of a chromosome, where certain things attach to that chromosome, whether body-cells have the receptors for the proteins coded by those genes, whether those body-cells actually act upon those receptors, whether particular hormone levels are enough to trigger certain actions in the body and - in the end - all kinds of other factors.
There's no such thing as XX/XY being the sole determinant of your biological sex. For a start, things can attach to XY instead of XX and vice versa, XYY and XXYY and things like that exist, and those two chromosomes are far, far, far from being the only things that modify your physical sexual characteristics, your genitalia, your fertility or any number of other visible, measurable indicators of your biological sex.
XX males and XY females are perfectly possible.
1-2 percent of the world are biologically intersex. That's the same proportion as diabetics, red-heads or epileptics.
If you know a red-head, or a diabetic, chances are you know someone that doesn't fit the standard school biological sex model. And for every 100 people who "think they're male", there's a chance that at least one of them is genetically / chromosomally / hormonally not - even if they have perfectly ordinary and functional genitalia indicating otherwise.
Now, how do you think that affects the *gender* that people have, if the biological binary determination you were taught in biology is actually so wrong?
It's never been as clear-cut as you were taught in school, same as it's never been true that an atom looks like you've been told it does.
Treating it as some kind of modern hippy fad, where people get to choose who they want to be (oh, what a crime!), is really quite a 1950's way of thinking.