Alright kiddo, let's talk about sex and sexuality in stories that we make up in our heads, called speculative fiction.
You know how sometimes stories have characters who are boys or girls, right? Well, sometimes stories have characters who feel like they are boys or girls on the inside, even if they look different on the outside. This is called gender identity. Sometimes a boy might feel like they are really a girl, and sometimes a girl might feel like they are really a boy. And sometimes people don't feel like they fit into either boy or girl categories, and that's okay too! Speculative fiction can have characters like this, and their stories can be just as exciting and interesting as anyone else's.
Now, let's talk about something else - love and attraction. You know how grownups can love each other and want to be close to each other, right? Well, sometimes it's not just a boy and a girl who love each other - sometimes it's two boys who love each other, or two girls who love each other, or any other combination of people! This is called different sexual orientations. Some people are attracted to guys, some people are attracted to girls, and some people are attracted to people no matter what their gender is. And, just like with gender identity, speculative fiction can have characters with all sorts of different sexual orientations.
Sometimes stories will talk about kissing or touching, which are things that grownups do when they love each other. We don't have to go into too much detail about that, but just know that people in stories can do those things with whoever they love, no matter what gender they are.
So, to sum it up - stories can have all sorts of different characters with all sorts of different gender identities and sexual orientations. And that's a good thing, because it shows us that no matter what we look like or who we love, we all deserve to have our stories told.