Did you know that gender is a social construct? It is the meaning attach to being a male or female body. But this meaning depends on culture, when in history we are talking about, in other words, it is not static nor is it inherent in people.
And although it has been suggested that this idea that there is a continuum of gender identity is new, it has been around for a while. Many cultures in many different eras, and on all continents have identified more than 2 genders.
Even at a biological and genetic level, there is more variation in sex than the two options most of us grew up being taught.
And when you are born and the doctor looks at your genitals and assigns a gender, this obviously does not take into account the how the person will see themselves. Of course it doesn’t. We all grow up and start developing a sense of personal identity.
One aspect of identity is our gender identity. For many who are cisgender, as in their sense of their gender matches what the doctor put on their birth certificate, they do not reflect on the ways they have constructed the meaning of their gender as they grow up. It is invisible to them, but it is constructed over time through experiences our own response to those experiences. Who we see ourselves as may, or may not, be congruent with our bodies or how other see and respond to us, but that makes it no less valid.
The above quote is from Geena Rocero, a model and activist who came out as trans.