I don't even understand where is the need for stating a person genre in his driving license. What's the point? The only data that you need is a photo, a name, and a list of which kinds of vehicles you are authorized to drive.
Eye color? Hair color? Height? What's the point? Can't you wear colored contact lenses if you drive? Dye your hair? Wear high heeled shoes? Pointless. Genre, of course, is the same.
In Spain, none of that data is displayed in any kind of ID. Instead, we have the birth date, probably pointless, too; but at least is something that really identifies you and you can't change.