Make your bathroom identifications XX and XY. Everybody has to be one or the other.
That’s not true about everyone. There are approx 0 3% of the human population that have some variation like XXY, XYY, X, Y, XXYY, and others. These people were all born that way and they will be that way for the rest of their lives. Most of them won’t even know they have this genetic variation during their lives. Depending on the variation they will grow male or female organs & most will live very normal lives. For all you know, if you read this, you are in one of these groups. If you don’t know for sure then go get your DNA tested. There is a chance, about 1 in 300, that you will discover that you have such a variation.
The third one: Other