My children have a very established view that boys are often boys on the outside, girls on the inside and vice versa. They see it akin to how you shouldn't judge people on appearances, it's what is on the inside that counts.
Before school taught about trans issues my eldest had a good grasp of challenging gender stereotypes. (We live in wokesville - no prizes for guessing where!)
My word doesn't count for much this subject. I wondered if there are any books or education materials that are really good on challenging stereotypes.