How to Work with Vocabulary Correctly, Exemplified with Gender Coding?

Popular data exchange standards facilitate the use of vocabulary in different ways. Quite often, the usage is based on, and in favor of, simple implementations not considering reality. In most cases the vocabulary is assembled in form of simple code lists. Well-known bad practice is neither to define proper concept descriptions for the individual codes leaving their interpretation to the developer nor to identify the underlying vocabulary domain resulting in a mixture of something. This paper takes the gender use case and analyses the use of codes within some data exchange standards and makes recommendations for improvements in handling and managing code systems correctly