Relationship between 'indeterminate' and non-binary individuals

Hopefully an easy question to answer. I’ve been tasked with updating part of our software to handle transgender & non-binary patients. The work relates to genomic medicine. As of such both a patient’s birth gender, and their current gender are relevant to care.

One of my questions - what happens when a patient’s gender changes? - was answered by PDS Administrative Gender Change.

My other question was, how does the ‘indeterminate’ gender relate to non-binary patients? Do these terms mean effectively the same thing, or is there a distinction that I’ve missed (e.g. it being possible to be ‘indeterminate’ without being non-binary for some reason). Essentially, I’d like to know if there is any need to store additional information on top of the patient’s gender on the PDS API in this instance.

As a side question, would it also be possible to find their gender-assigned-at-birth via the PDS service, or is this something that would need to be stored separately?