Something that has been helpful for me when having conversations about what counts as intersex is to really engage in enquiry about what the label means and how we're using it. To me, it's been more helpful to think through questions like:

What purpose does labeling a variation as intersex serve?

In what ways is societal understandings of "typical" changing?

Why was the label of intersex created and has our use of the label shifted?

What ways are we building intersex community? What do we want intersex community to look like?

How do our experiences of oppression impact our understanding of intersex as a term?

What sources are we drawing from when we develop definitions of intersex?

What is the history of the way intersex has been used?

What ways has intersex community been exclusionary in the past, and is that in line with our current values?

Definitions of intersex have always been tied up with what the medical world decides to classify as differences of sex development, but especially in the past twenty years as intersex community has grown more connected, we've started to have a lot more self-determination in our communities. But I think a lot of people still really have a misconception that intersex is a biological "third sex" that is strictly medically defined, and that there are clear cutoffs between intersex and endosex.

Instead, I'd like to bring in the concept of compulsory dyadism to introduce a framework where intersex is an intentional political label used as a way to build community for the people whose variation of sex characteristics are most impacted by the stigma and violence associated with compulsory dyadism.

Sex diversity is not just limited to intersex people. Even within the boundaries of dyadic/endosex bodies, people have variations like different amounts of body hair, penis size, hormone levels, breast size, as well as things like disabilities affecting any of those traits. For example, very few people actually have all the "ideal" traits that line up with this constructed idea of an endosex body that has the exact "correct" amount of estrogen, the right size chest, the ability to bear children, "normal" periods. Many endosex people might have a variation in one of those aspects at differing times during their life, such as during menopause, for example. And this framework can help us understand how diagnoses such as endometriosis are not intersex, but people might still notice overlaps in certain experiences.

But the reason that not everyone is considered intersex and the reason that having a separation between endosex and intersex is important is because of the stigma and violence associated with straying further and further from that dyadic norm, and intersex is a label used to describe people who are the most impacted by that stigma and violence. We have been socially labeled as "deviating" the most from the "normal" sex binary, and consequentially face intersexism both on a systematic and personal level. Our collection of sex variations becomes located entirely outside of the sex binary, and as a result, we often face curative violence, social stigma, and systematic exclusion from many parts of society.

This definition isn't a perfect definition. I think we need to have room to develop more nuance around the fact that many intersex people might not feel like their experience of being intersex has brought them any personal stigma or violence, as well as understanding that there isn't going to be a universal intersex experience. Even when discussing how intersex people are the most impacted by compulsory dyadism compared to endosex people, I think it's important to recognize that within the intersex community, our additional intersecting identities are absolutely going to influence our experiences with oppression and that it's vital to intentionally uplift the members of our intersex community who are most impacted by oppression. In the United States, the creation of the sex binary was an explicitly racist process, and racialized intersex people are subject to additional layers of stigma, violence and scrutiny. (Check out chapters 4-6 in the book Cripping Intersex by Dr. Celeste Orr for a really in depth discussion of how antiblackness and compulsory dyadism are forces behind why the Olympic sports sex testing has pretty much exclusively targeted Black women from the Global South, regardless of whether or not they are actually intersex. Also recommend reading The Biopolitics of Feeling: Race, Sex, and Science in the Nineteenth Century by Dr Kyla Schuller.) I also have talked with many intersex people who are tired of us always being represented through trauma narratives in the media, and who want us to be able to build a definition of intersex that isn't based around violence or tragedy. And I think that's really important that we also share our stories of intersex joy, and pride, and healing. I think that claiming intersex can be something really radical, and that's super valuable to me.

Overall I think that if we build our discussions around who is intersex on concepts to do with our social and political location, and take into consideration concepts like compulsory dyadism, sex diversity, and disability, we are going to be able to understand why any of it matters better than if our determinations of intersex identity are based solely in medicalized concepts of a third sex.

TL;DR: Although endosex people also have diversity when it comes to sex traits, intersex is still an important label that not everyone can claim. Compulsory dyadism is a force that affects all of us, but intersex people are the most impacted by compulsory dyadism and face intersexist stigma and violence for our intersex variations. As a result, intersex is an important label for us to claim so that we can build community and solidarity around our experiences. I think it is better understood as a sociopolitical label that describes the relationship between our biological bodies and the cultures we live in, rather than as a medicalized term that described a coherent "third sex."

other intersex people feel free to add on to this post-I'm only one person without all the answers, and would love to hear other perspectives!