In 100 years, when they dig up a body they will still test the bones to determine the gender of the individual. They won't care about the person's self exploratory journey to discover who they are on the inside or worry about how they identified...
I'm very curious as to exactly what kind of archaeological studies you think are taking place that only care about the sex of a deceased individual and not how they actually lived (when the latter is, um, kinda the whole point of archeology). Are you sure you're not thinking of necrophilia? 
Taking it a step further, they can't even say what a woman is.
Why would you expect them to? Dividing things into categories is a matter of taxonomy, not science, and taxonomists can't even agree on a definition of species that works in all cases. Rigid adherence to established biological taxonomy is how you end up making absurd statements like "tomatoes are technically a fruit", "viruses aren't really alive", and "there's no such thing as trees".