Sex: ‘X’ (Indetermined)

Today I got my new (German) passport which includes a small but important change of my personal data: now in the field sex it shows 'X' for 'indetermined'. I thought for a long time that it would not really be important what these official documents say. However, I am getting more and more tired and annoyed of always having to choose between two binary options on any form, when I buy something on the web (for example an airplane ticket), and on many other occasions. I am aware that it is not very likely that this will change quickly with the new passport - I see it more as a tool.

I don't live in Germany, I live in the State of Spain. I don't have any idea what might happen now. According to Spanish law, at least to my knowledge, the option to leave the field sex empty (meaning: indetermined) does not exist in any form or questionnaire. Neither is there another positive option, for example, to put "genderqueer" or any other non-binary definition under the field sex. At the same time, they (the administration) want that their data (of the Spanish State) matches that of Germany (if not, I would be 'male' in the Spanish State, and 'indetermined' in Germany).

For example, my bank has replied to my request to change my personal data about two months ago in the following way:

"As a banking institution, ... we have among our obligations to identify our potential clients, and sex being one of the characteristics which appear in the identity dcouments provided by the states to their citizens, concretely, we refer to your passport (as you are a non-Spanish EU citizen), where as sex it shows 'M', which is information we need to conserve, and even though it might only be in strictly legal terms, this is information this institution cannot change or modify. Following from this, while the presently valid laws are not changed in a way that they would recognise your third gender or the option not to define oneself, we cannot respond positively to your request."

This was before my new passport. The logic of what they say means that now they need to conserve the new information in the field sex - the 'X'.

The same I would like to try with several other Spanish authorities. Social Security? The Health Service of Andalucia? The Registry of Inhabitants of Sevilla? The Tax Office? Wouldn't they need to align their data with my new German data?

I expect this to be an interesting journey.