Lacking the words for it is so real. I'm working with 2-3 year olds and a big part of what I'm doing this year is helping equip them with the understanding of gender (including the words to describe these things) and working with staff on anti-bias and how to recognise their own.
It's refreshing to see how so many kids by the time they're hitting primary school are knowledgeable about this stuff. I know one primary school near me as 'theys' toilets along with the boys/girls toilets. I am so excited for these generations to grow up and start running things.