also, people are born with gender differences in the brain, they just mostly don’t realize it until puberty or later in life. The brain develops at a different time than the genitals and it’s possible for the body to pull a switcheroo in that time

also the brain is complex and some ppl with this are fine being the gender they were born with and others without it are trans too. Rule of thumb is just take what people tell you they are and go with that.