I heard this yesterday - mum asking her little girl (about 4 or 5 years old) how do you know you are a girl?
To be fair I regularly ask my three year old this. I am trying to teach him correct names for his anatomy and him answering 'my penis' to what makes you a boy, not only protects him from predators using children's lack of language to describe abuse, it also is an inoculation against gender ideology.
I would probably be accused of 'celebrating' my son's gender non conforming choices too much, but that's because it is almost a hyper awareness. Goes something like this.
What do you want pink ladybirds or blue slugs.
Pink ladybirds
internal voice: he's chosen pink. Will he get bullied? Better check?
you're sure?
Yes
internal voice oh no, have I just undermined his choice? Quick, undo, undo.
Great choice son!
Personally I believe that you actually have to ensure you don't completely colour code either gender, as there's no point telling 8-9 year olds colours are for everyone when most children have been colour coded since birth and they can see in their experience it's not true. If all they see is boys in blue and girls in pink they are vulnerable to gender ideology if they do not conform to gender norms. And let's face it, everyone transgresses stereotypes in one way or another.
I've tried to teach my son all colours are equal. My hope is as he doesn't see pink as inferior, he won't see girls as inferior. And if he doesn't like blue he won't think twice about purple or turquoise.
But from the outside superficially because he occasionally wears pink, purple, cats, birds, butterflies and flowers it'd look like I'm trying hard to make him gender non conforming. If you saw him on a firetruck, trains or sharks day you'd think the opposite.
Sometimes he mixes it up. I don't know what you'd think other than he's got no fashion sense haha!