Uniquely, perhaps not, I'm not sure I said that. However, we have had sexual reproduction for 2 billion years. There can't be many features that differentiate us one from another that are as old, and as thoroughly baked in to us. What are the core things that a human needs to do to survive? Eat, find shelter, and have sex. Recognising, and finding important, the difference between men and women has been critically important, and has been critically important for millions and millions of years. It is very clearly baked into brains across the animal world from penguins to elephants. Very frequently you see differences in behaviour, and differences in role in the animal world, just as you see it with us. This again is not surprising because for one thing there is a function that only females can perform. For another, in times of threat, the value of the sexes is not remotely the same as one another.
What other cultural architypes are you thinking of that are remotely as significant? Are there any that you can detect the differences between in the behaviour of new born babies, that we have different hormones and so forth to steer? Thinking that society can make these differences inconsequential is like thinking society could regard food as optional. Sure there are cultural rituals around food, but they are build upon a basic physical reality and necessity, just as gender is.
Believing all this stuff is optional, and arbitrary is like believing in breatharianism.
There is a saying you see going around on the dissident right that comes from Spengler:
“When the ordinary thought of a highly cultivated people begins to regard 'having children' as a question of pro's and con's, the great turning point has come.”
He is saying that when having children isn't just something you assume you are going to do, the civilisation is doomed to collapse. I think that pretty easily extends to people acting as if they don't know what men and women are. There are core tasks that civilisations need to do to survive, and we seem to have decided that one of them is optional.
Sure, we live in a decadent age where people have ridiculous beliefs that in harsher times would have got them slapped round the head and made to do something useful. Trans stuff is just an even more silly, decadent belief on top of previous only marginally more sensible ones. They are peacocks tails. These things aren't so bad when it's just a fringe aristocratic fad. If it spills out though, it's like if the Chinese had decided they were going to normalise foot binding, and you'd had peasants tottering about the fields.
What we haven't evolved to do is live in a vacuum. We've evolved to adapt to environments and environmental factors. Factors such as, for instance, population.
Did Spengler happen to notice that if your highly developed culture is overpopulated well beyond the carrying capacity of the environment, having more children doesn't help? Unless, of course, you plan to arm those children and send them off to fight for some other region's resources, which will either obtain said resources or kill off the children (or both), momentarily relieving the population pressure. Is that the natural non-decadent evolved system we should be preferring over "marxist" theories that defy "nature" by making having children optional? If so, those advocates might not have taken into account the current capabilities of weapons (another aspect of the current environment) and their side effects on infrastructure. Infrastructure that has elevated the carrying capacity of the environment. See the problem there? The "natural" consequence of breeding more hungry soldiers in that case is not temporary relief of population pressure, it's fueling collapse.
If alternate lifestyles that stop people from having children are unnatural and contrary to evolution, why are they ubiquitous in various forms (eunuch classes, monastic religious celibates, all-male pursuits with low survival rates) throughout known history? Why is it any surprise that extreme forms of them would arise at a time when both population and the success rate of attempted reproduction (survival of pregnancy and infancy) are unprecedentedly high?
tl, dr: I see the dissident right's Marx and Spengler and raise them a Malthus and a Darwin.