That’s just the thing. One side isn’t using scientific evidence. There is a process to science. You can’t use the simplified version of gender taught to kids and say it’s scientific. Just like you can’t say that the year is 365 days long like kids are taught at first. Then they learn about leap years and it’s actually 365 and a quarter days. Then they learn about leap seconds. Ok so then there must be some fraction of a second in addition to the 365.25 days. Then they learn about wobble, the gravity of the planets, and everything else that makes it not a constant. It’s something that has to be analyzed every year to decide if one is needed yet. It’s complicated. So just like kids are taught 365 days in a year, they are taught that there are 2 genders that are caused by one of two combinations of chromosomes. Then they learn about intersex people and people born with vaginas who have an x chromosome and people with 3 chromosomes, etc.
So sure, if you’re a child it’s ok to think there are two genders chosen based on a single chromosome difference. But it’s not ok to pretend it’s that simple and call it truth and scientific evidence that your teachers taught it that way.