In a similar vein, I don't understand people who want to know their child's gender before birth. Even ignoring the whole transgender and non-binary aspect, it's like they want to have their kids figured out at birth.
Or maybe it’s just so easy to find out the gender during medical screenings that you have to not look on purpose, so why not look? Then you don’t have to go out of your way to plan for two (pretty much) mutually exclusive possibilities.
Parents who want their children’s paths predestined don’t have a “knowing the child’s gender” problem, they have a “you can’t control your child’s basic personality” problem.