If one models gender as a boolean switch that can be set to either "male" or "female", and encounters an individual who has a combination of "male" and "female" characteristics, their model may not accommodate the new observation.
So did the person have a Y chromosome or not?
This misses the point. There are other aspects that in a subset of the population get more complicated and not so clear cut.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.