In 100 years, I could imagine a society where young people are expected to find a gender identity in the same way as they find other aspects of themselves, and maybe their gender identity changes a few times over their lives.
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... Science is science. I find it absolutely insane that the party of science who bashes the other side constantly for not agreeing with their "research" can deny that gender isn't something we choose. Taking it a step further, they can't even say what a woman is. Only that they identify as one. I think to be a modern day liberal you either have to suffer from serious mental illness or you are so set on having your way by any means possible that you look the other way at all the nonsense and stay focused on growing your numbers to get your way.