If nonsexual reproduction becomes the norm, then which sex you are will become far less important. I don't think it means that which sex you are is no longer true, it will just be a much less notable fact if society becomes so dependent on technology that we create all our young through nonsexual means and do not use our reproductive systems.

If those reproductive systems still exist in our bodies, then we will still be that sex, though, and it will still have some effect on the way that our bodies work - female bodies have a whole extra internal organ system that male bodies do not have, to prepare for and eventually bear a child. Female bodies menstruate regularly in order to be able to do that. Maybe in your high tech asexual reproductive version of the future female bodies are routinely altered since these systems aren't needed anymore? They would still need to go through additional surgeries that male bodies wouldn't need. And males would still have the penis, testicles and prostrate that a female doesn't, and additional doses of testosterone throughout childhood. It just comes down to the distinctions of the bodies that we have in preparation to be able to create the offspring. We can come up with alternate ways to procreate, but naturally we reproduce sexually and that means there are two types of bodies. We can alter them, but we can't turn them into each other. We can find other ways to make young, but that still doesn't take away the bodies we have.

The future may be very different in many ways and sex may become less important as a category going forward, but it is still relevant today and should not be erased in confusion. Even when it theoretically becomes less important, it will still be a fact.