Gender markers

Gender markers are data points that show the gender of a person on a document (such as passport, driver's license, insurance card, birth certificate, etc) or in a computer system (such as an employee database, electronic health record, etc). Sometimes this data point is called "Sex" instead of "Gender", but depending on the applicable laws the marker might be able to be changed without the person having surgically changed their sexual organs.

The standard common gender markers are M for male and F for female. Other gender markers (which are not always available) include U for unspecified, O for other, E for eunuch, and X for a nonbinary or intersex person (although many intersex people have a gender identity of binary man/woman).

Even when a U, O, or X option is available, not all nonbinary people will be comfortable selecting it.

Some transgender and nonbinary activists hold the view that gender markers are unnecessary and should be done away with.