You make it sound like all an 8-year-old trans person has to do is go to their doctor and say, "You know what? I wanna try being a boy/a girl." And boom! the doctor hands them powerful drugs and schedules surgery for the next day.
It's an expensive, complicated, drawn-out process that involves a lot of psychological evaluation. It's not a fad and it's not a whim. And it's none of your business.