Worried it’s an issue? It doesn’t have to be. Just because you’re including something that can be an issue, that doesn’t mean it has to be in your work. For instance, not all gay teens are bullied (thankfully). If the Shiny New Idea you’re plotting doesn’t include that specific element, that’s fine. This isn’t to say they aren’t topics worth exploring! Only that it’s completely believable and acceptable to have an array of different characters even if your book’s central plot is about a wizard lost in a dystopian world. HOWEVER, though it might not be an issue, to fully understand your character—their thoughts and actions—you need to see the world absolutely through their eyes which means while they may not be experiencing teasing or harassment, it doesn’t mean it didn’t happen in the past or isn’t something they're constantly hyper-aware of. These are all things that can play a part in a character’s, well, character.
Feeling like you just don’t know enough to include something new in your work? Well. That’s an easy fix.
There’s a difference between ignorance and stupidity. Neither is an excuse. Do your Research!
A search engine will pull up a multitude of information. Is all of it correct? Nope. But some will be, and it’s a great place to start. Between there and the library, you could easily learn a lot of surface information. If possible, dive deeper and try to find someone to interview or even observe (in the least creepy way possible) for a real glimpse. Find out what tops interest in their world—read newspapers or articles aimed at the community you’re researching. Of course, nothing would compare to actually submersing yourself in whatever culture it is you’re writing about if that’s a possibility!
It might feel like a lot of work for developing a background for one simple character. What you take away might only result in a sentence or two in the entire book. But readers do notice it and appreciate it. (Not to mention, you’ve learned new stuff as well!)
Even after researching, make sure to address things with sensitivity.
I was brought up strict Catholic (in a town that was strictly Baptist). Trust me when I say Mary Katherine Gallagher was one of my favorite Saturday Night Live skits. But it was hard to laugh as much when it was a classmate poking fun of my religion. Characters comfortable in their own skin might be quick to poke fun at themselves, but remember this could be a first impression for some readers. Think about what you want them to walk away remembering.
And lastly, try your best to avoid the stereotype. Before our move to Spain, I did some light research. Things to do, places to see, cultural differences. One thing I wasn’t prepared for was to see so many fair complexions and blue eyes. In my mind, I imagined all Spanish people with gorgeous olive skin and dark hair. If I’d done just a little research into the history though, I would easily have seen how they’re very much a mixing pot like the US. Needless to say, whatever image you’ve already formed in your head, might not always be right.