[HarrietJones]

Well - Yes and No.

My view on this is you have both gender identity and gender expression. Gender identity is very important to people and (to a lesser degree, children), but it's (mostly) invisible. We even hide our most obvious sexual characteristics.

For this and possibly other reasons, gender identifiers are important. It's important that we (cis and trans both) can hold the magical tchotchke of womanhood and wave it about so that other people know what we are. If it wasn't important that people knew what we are we wouldn't spend a fortune on dresses and makeup.

How that gender identity is defined isn't important. What is important is that it is defined. I'd argue that as long as it doesn't impact on a persons life choices then we should have things for boys and things for girls. So - Javascript is for Boys is a bad implementation of Gender Identity. Pink is for Girls is actually a great expression of Gender Identity. (As it doesn't affect career, or ease of getting dressed or anything that may otherwise societally affect women).

Of course this whole conversation is full of mentalists shouting at each other, so we're never going to be able to work out the best way of allowing gender fluidity in children or for trans people to live in the world without being labelled as mentally ill.