1. people are purely hard wired to a particular gender.
2. gender is a purely social construct
3. Birth sex/genetics/epigenetics strongly influence behavior.
However desires and opinions are strongly swayed by mimetic influences such that people change frequently, especially if they are young
Not saying truly transgender people don't exist but the huge explosion in numbers since it became socially acceptable means that either there's "something in the water" which is increasing the number of transgender people around, or a lot of vulnerable young people approaching and going through puberty and feeling confused and different are convincing themselves they're transgender [because it's all over the news], where back in my day they'd be fretting that they might be gay.
I think the danger is in the fact that, for someone at that vulnerable age, convincing yourself you're transgender can lead to you undergoing life-changing, physical alteration to your body, where convincing yourself you must be gay might have lead to a few embarrassing memories, in later life.
They practically universally have strict, intolerant and conformist opinions too.
Quoting her from "Little Boxes", 1962:
And the people in the houses
All went to the university
Where they were put in boxes
And they came out all the same
And there's doctors and lawyers
And business executives
And they're all made out of ticky tacky
And they all look just the same
And they all play on the golf course
And drink their martinis dry
And they all have pretty children
And the children go to school
And the children go to summer camp
And then to the university
Where they are put in boxes
And they come out all the same
And the boys go into business
And marry and raise a family
In boxes made of ticky tacky
And they all look just the sameIt's also the theme tune for the series "Weeds" (TV series).
Unless you allow an indefinite (and large?) number of genders, to include at least each of the option at https://en.wikipedia.org/wiki/Non-binary_gender as a hard-wired gender?
Which leads to the question: How many genders are in your 3-option model?