If there’s a topic in the modern era that creates instant controversy, it’s gender identity. Social media trolls adore this subject, because they know they’ll get impassioned responses and traffic from all sides.

But beyond the trolls who deliberately fan the flames, plenty of other people make honest errors about evolving gender identities. Many of us who aren’t in the center of these worlds don’t yet grasp all the nuances of contemporary gender identity, and mistakes are easily—and not intentionally—made.

So, in the spirit of educating people who genuinely want to learn, and who perhaps might even be an ally to those who face the challenges of living with a nontraditional gender identity, here’s a brief primer on modern gender-identity labels.

But first, a quick disclaimer: This list is not meant to be comprehensive, nor does it pretend to be authoritative. The sands upon which these terms are built are constantly shifting, just as society’s attitudes shift alongside. Please take this in the spirit in which it is intended, one of support toward better understanding.

Gender binary