> You vastly underestimate the complexity of the human genome
We mapped it out 20+ years ago. We learn more about it each year, but what's more, the extent of our knowledge increases exponentially, not linearly.
> Ontogenesis, epigenetics, environmental factors, ... there is a lot more on sex variant hardware front than genetics.
You act like these are factors that can't be controlled, if not entirely, at least to some degree.
> at that point of understanding and manipulating human biology
We are very nearly at that point. Within anywhere from 20-30 years, maybe even less. If you think "people" will have moved beyond limiting categories in that time, you're not thinking clearly about the past, but what's worse, you're not thinking clearly about humanity.
If you think we'll end up in a Star Trek-like world before we have the ability to successfully manipulate the genome, you can just look to the fictional history of Trek for that... we were supposed to be in the middle of the Eugenics Wars right about now. Turns out they'll come later, I guess.