This is a fun topic, weaponized by the stupidest and meanest people. At birth in western culture children are assigned one of two genders based upon their genitals (gross right?): boy or girl. And usually presumed heterosexual until proven otherwise (that’s another article).
The only exception (barely) is intersex, a person who does not have clear male/female genitals. However for much of our modern history these people were forced into a gender upon birth regardless of how they felt. Many suicides happened because of this. There are currently 64 cultural genders and 74 non cultural known genders, which I feel can be broken up into 5 main groups (yes there can be overlap). 134 genders total.The Gender Wikiis a good resource, only on the more obscure genders it lacks info and can be confusing for people who feel they may be that gender (see agender). I’ll do my best with links.
CIS
A person who is cisgender is either cis male or cis female based on their genitals at birth. Well into the 90s it was believed humans only had XX (male) or XY (female) chromosomes. Resulting in many female athletes to discover their chromosomes don’t match their genitals. There are currently now known (2024) to be 23 chromosome that determine gender. Proving genitals is not the best option for understanding sex.
How do you know if you’re cis? You feel the gender assigned at birth is correct. You do not experience dysmorphia about being called the gender you were assigned (i.e. if you are cis female and someone says you’re a pretty girl that doesn’t bother you). And one hitch that accidentally queered a bunch of cis people: you don’t feel you’re performing gender. You would be offended if mistaken for a different gender (usually opposite cis of your assigned gender).
If you are cis you can be referred to as assigned female at birth (AFAB) or assigned male at birth (AMAB) but not just people are called this. You may wish to have gender affirming surgery to your assigned gender (breast implants for women, hair transplant for men etc). Pills such as birth control and Viagra are also hormone based gender affirming medicines. Which makes many complaints about non cis people rich. You may someday realize you are not cis, or maybe you were all along. Read on! But there is no shame in questioning gender. CIS may also be called the Binary (as in two).
Genders under CIS (cis is the only gender dependent on genital presentation):
Cis Male
Cis Female
(Please note a gender like agender can be considered its own gender, or also nonbinary/queer/trans. Many genders and gender groups can be mixed and matched and often are. Not everyone in one gender (example: agender) may feel they are the same mix of genders/groups. Once you’re off the binary its pretty free movement. This may be hard for cis people to understand, but it just is. Accept it as presented by a person.
Quickly summarized as you were assigned the wrong gender at birth. You feel you are the opposite gender. Many nonbinary people (who reject binary/cis) also feel trans.
Quickly Summarized as: A lack of gender. You reject the binary as default. You may feel trans/queer as well.
Quickly Summarized: lack of cis/binary. Very wide gender category
Quickly Summarized: a gender you can not be unless you are part of the culture from whence it came
Quickly summarized: a person born with any number of genomes and/or external genitalia that does not match the cis binary