The movie profiles three intersex people and describes what it means to be intersex. Prior to seeing this movie, I did not know that intersex people existed. These are people whose physical genitalia doesn't match the normal presentation for their chromosomal sex. For this reason, these are people for whom gender at birth is ambiguous, since they have biological traits of both genders.
This first great thing about this movie is that it presents cases where the phrase "gender assigned at birth" makes sense and is explained! I'm a liberal voter, but have bristled at how trans vocabulary uses "gender assigned at birth". I never got it- how could gender be "assigned"? By profiling intersex people, this movie explains cases where in fact gender is very deliberately chosen.
The second great thing about this movie is that it presents intersex conditions simply as "different bodies", people for whom a typical combination of chromosomes and genital anatomy didn't happen. I think most people can point to something that makes their body different from "normal"- intersex people just had this happen when it came to their sexual anatomy. The concept of "different bodies" really humanized intersex, and by extension, trans, people for me. You can physically see on an intersex body why gender is ambiguous. What's not to say that trans people had different sex hormones in utero, and their brains are different? In order words- trans bodies are different too- we just can't see the differences?
Finally, the third and last great thing about this movie is the story told by Alicia Roth Weigel. She is a beautiful, blond-haired, dress-wearing, very feminine looking woman. If you saw her on the street, you'd think she is a typical woman, but she has XY chromosomes! She is the perfect spokesperson to show that genital anatomy and chromosomes together don't fit perfectly into two boxes. Trans stories are often told by people whose physical look is atypical for their gender. Ms Weigel tells her story as someone who identifies as a woman and also looks very feminine.