If a student can claim to be the gender other than their own, they can claim to be another age.
"I'm not 14, I identify as 41."
"Mommy, I wanna be a snake. Can I cut off my arms and legs?"
"No."
"Why not?"
"Because you're five and that's harmful."
"Mommy, I wanna be like Ernie from Sesame Street. Can I cut off one finger on each hand?"
"No."
"Why not?"
"Because you're five and that's harmful."
"Mommy, I wanna be a girl. Can I cut off my penis?"
"Sure. You know what's best. Mommy will sue the doctors if they won't do it."
Your exchange demonstrates the insanity of what is going on right now re: this gender reassignment surgery for children.
It does seem that parents must have been hypnotized or brainwashed or otherwise conditioned to behave insanely in this matter. Nothing else explains it.
The urge to defend one's child from danger is one of the most powerful and innate of all human instincts. Something had to happen to these parents to destroy that behavioral response. It didn't just go away because they (the parents) saw other parents change. This is not an urge that is can be amended by herd consensus or popular trends.