Here is the situation as I see it: There are two words, 'man' and 'woman', and there are two concepts competing to provide the definition for those words: biological sex and gender identity.
Biological sex, we know. It has been around longer than any of us have, and it is found everywhere in nature. Biological sex is based on physical, observable, empirical evidence. It is provable: If I claim to be a man, I can prove it through empirical evidence. And it is falsifiable: If I claim to be a woman, you can disprove my claim through empirical evidence. Yes, there are the rare cases where, due to birth defects, physical ambiguity exists making the distinction between man and woman less clear, but those cases themselves are provable through empirical evidence. In every case, biological sex is provable as well as falsifiable. It is something we can know—actually know—about each other.
And then we have the new kid on the block, gender identity, that is also competing to define the words 'man' and 'woman'. Gender identity is a new concept. When you were young, did you ever imagine we would be having this controversy? Probably not, and yet here we are. Gender identity is the belief that the definition of 'man' and 'woman' should be based on personal identity instead of on physical reality. It is unfalsifiable: If a biological male claims to be a woman, gender identity provides you no way to disprove that claim. You aren't allowed to disprove it with physical observation. You aren't allowed to disprove it with DNA tests. You aren't allowed to disprove it with brain scans. You aren't allowed to disprove it at all. Gender identity is as unfalsifiable as any other religious belief. And because gender identity is unfalsifiable, it is also unprovable. You cannot prove something you have no way to disprove. Proof, scientific proof, requires a two-way street. Gender identity is based entirely on blind faith. Someone claims to be a gender and you are just supposed to believe them. They could be wrong. They could be joking. They could be lying. There's no way for you to really know.
So, let me get this straight. We have these two words that need a definition, 'man' and 'woman', and we have two concepts competing to provide that definition, biological sex and gender identity, and for some incomprehensible reason we've decided as a society to prioritize the unprovable concept over the provable one? We've decided to let gender identity override biological sex?
• Gender Identity Is a Religious Belief That I Don't Believe In
topic: gender identity