Would my skin colour and gender fall under that definition?
More to the point, talking about sex and gender in the same breath is quite often absurd. Gender theory is a sociological theory, not a scientific one, and while sociology is a useful tool for certain problems, it's hardly reproducible, or falsifiable.
Edit: on second thought, we're not so much in agreement as nothing is fully genetic or environmental. There are, for instance, cases of XY females. I'd agree if you said the genetic link was orders of magnitude stronger between genes and sex, but the "100%" perpetuates a common misunderstanding of genetics.
I suppose you could induce something like that by treating an embryo with finasteride or another SARM but there's a reason such drugs are in pregnancy category X. They tend to produce wider ranging and more severe defects than just changing the sex of the embryo. Hormones are complicated.
The real question is whether or not we, as a species, can be trusted with the unprecedented power and responsibility of direct control over our own evolution. Modern medicine is fundamentally dysgenic. My line alone has tendencies towards bipolar disorder, poor vision, asthma, and crippling congenital foot defects. I was fortunate to have escaped most of them. However, the mere fact that I was born carrying these traits can be credited to the fact that my grandparents were treated for them (club feet in the case of my grandmother) and survived to pass them on. Great for the individual, but in the cold calculus of survival, it can only be said that the more serious genetic maladies that we can correct for with medicine and surgery, the more they will build up in the gene pool.
The promise of these new gene modification techniques is that we can put the hands on the wheel of our own genetic destiny rather than leaving it to the Ouija-board control of whatever god one would choose to cede them to. One might well expect this thought to make a great many people very uncomfortable. This is entirely justified given the human track record.
However, another ethical standpoint to take might be this: If I am told that my child, in utero, has a 100% chance of being born with cystic fibrosis, but that a reasonably priced (hey, it could happen) treatment could apply a patch to that nasty little mutation, would that somehow be less ethically sound than abortion, abstaining from childbearing, or allowing the child to come to term to a life of certain, now trivially preventable, suffering?
Contrarily, if the burden depressive moodiness is 'cured' from our genetic makeup, what cost do we pay in losing the creative pearls built up around the pain of the melancholic soul? A world without Poe, van Gogh, or even Morrissey?
Tough questions.
No. Check back in 50-100 years.
The interesting case, is that our long-term survival is now more a question of information, culture, and knowledge than it is of our biological capacities. Our most interesting evolution is happening in the rapid and ephemeral'software' of shared knowledge and technology, and not the fleshy hardware ruled by genes.
And you're probably wrong about saying you'd be dead; why did your ancestors survive it?
Cave dwelling fish don't lose their eyes because of any immediate selection counter pressure, but from the slow reversion to the mean from no pressure either way. Or maybe the small pressure of nutrients spent on maintaining a useless organ.
Perhaps my example of my own case was misguided - I was turning blue and rushed to the emergency room as an infant, though. It was a single case provided to demonstrate a point where no single case matters that much.