I’d also add the consideration that a photo ID also serves the purpose of some base level medical information (or else our listing organ donor status on them is super weird) so having sex on there if you’re unconscious and the EMTs pick you up and need to check makes some sense. No reason both couldn’t work.
I mean you can be unconscious for more than head trauma. My thought was in line with heart issues and if the differences in sex played any part there, due to the differences in the appearance of problems with them between men and women, but maybe that’s not really relevant until they hit the hospital.(Since EMTs are stabilizing focused) Just having it on the card - avoiding the time needed to check especially if they’ve had surgery - seems helpful, if that was relevant. If its not of course it doesn’t need to be there but if there’s EMTs around chime in because obviously I don’t know.