From 'Bish' website for teens. The founder also provides resources/training for schools, youth groups etc:
July 13, 2017 'What’s Your Gender?'
(extracts)
"If you’ve had some basic AF sex education you might have been taught that there are only two sexes and two genders. Wrong. Sex and Gender is a lot more complicated than that.
You get to choose your gender your gender identity, whether you are a he/she/they or zie and you get to choose how you want to do your own gender. This is true no matter what body you may have, or what chromosomes you may have or how you feel about your body.
You can work out your gender by learning some more about different identities and seeing if any of those fit you, or you can try to understand your own unique gender for you. Hopefully you will find this [diagram opposite] useful" (continues)
For one, like I point out in this article, sex is a very complicated idea. It’s not just about our chromosomes (a lot of people don’t know what theirs are, XX, XY, XXY … ) but also; which hormones kick in, when they kick in and how they kick in; and then how genitals may take shape. Our genitals are on a spectrum in terms of: how much erectile tissue sticks out (clitorises and dicks and inbetween); where the prostate is; where the wee hole is; whether the gonads are inside or outside; vagina size. Many people are in the middle of this spectrum with how their bodies are configured.
Also sex, like gender, is not just about biology but is also to do with how we feel about ourselves and what society tells us about ourselves – it’s biopsychosocial."
www.bishuk.com/about-you/whats-your-gender/