But the easiest one I can explain is that this trend was clearly temporary as you and your mother acknowledge. Whereas the history of transgender people in humanity goes back to ancient history and carries through societal trends and gender role evolutions.
The more biting thing I can say is just because "<Something> is a trend", doesn't mean that "<Something else> is a trend too."
It always confuses me how on a site for techies, where people constantly reason about with virtual concepts and abstractions, the idea that physical biology genes and hormones might be typically but not EXCLUSIVELY coupled with mental sentience is so difficult to imagine.
I personally struggle to understand why a site full of techies can't see the human body for what it is, a genuine masterpiece of engineering with the clear and unmistakable hallmarks of purpose and higher order systems design.
Which, in our experience as engineers, is only ever the product of deliberate intelligence and any claim of exception should really raise eyebrows. Anyone who builds anything should have no trouble with this.
Based on that, I don't believe that the human body was designed for gender fluidity, in fact it is clearly deliberately set up to be binary. Any deviation from that default, in human beings, is unintended error. Perhaps due to deleterious genetic mutation or other entropic effects normally seen in complex systems.
Regardless of what you believe though, the safest thing to say is that we don't fully understand the systems in the body yet, and so Chesterton's Fence should apply. And ESPECIALLY so, when it's deciding whether to perform irreversible surgical work on a vulnerable population.
How many contractors arrive on site and incredulously say "what was the last guy thinking?" and actually mean it?
Just because we don't understand the reasoning yet isn't strong evidence of incompentant designs, it's more evidence of our own incompentance.
We used to think that the appendix was vestigial and useless, we used to think that 'Junk dna' was a thing. With more time and research we now know how wrong we were. I'll take the downvotes and predict that we'll keep finding out how wrong we are long into the future on this subject.
(I have to assume you must not know what the laryngeal nerve point is even about. Google "laryngeal nerve giraffe". Also try "blind spot why do octopus eyes not have it".)
Apply this type of thinking to anything else, and you'll never arrive at accurate or useful outcomes.
You're just deluding yourself.
So medical practitioners provided a 'solution', cutting a chunk of bone out of both legs to reduce height. (Usually reserved for people with asymmetric limbs.)
She desperately wanted to get this major surgery because she had tall poppy syndrome and didn't like life as the tall girl in high school. Her parents said no, it wasn't a real solution to her anxiety. She tells that story today and still rolls her eyes at herself for wanting to go through with it.
My heart breaks for these kids who've been enabled by their parents into getting irreversible body modifications. The worst part is that they feel rushed to make a decision because of the puberty window. This is a horrible time to be a child and a parent, truly.