It's never made much sense that the entire multi-species Federation would be subject to a strict ban on genetic engineering due to events on Earth that happened centuries before the Federation was even founded. The way they doubled down on that rationale in Una's trial only highlighted the absurdity -- especially when Admiral April claimed he would exclude Una to prevent genocide.
On the one hand, the writers may be trying to create a straw man out of a weird part of Star Trek lore so they can have a civil rights issue in Starfleet. And that's fine. From an in-universe perspective, though, I think we can discern another reason for the ban on genetic engineering -- the Klingon Augment Virus.
There was a ban on genetic engineering on United Earth, which is understandable given that it was much closer to the time of the Eugenics Wars. Why would that remain unchanged when more time passed, more species joined, and more humans lived in places without living reminders of the war? [NOTE: I have updated the paragraph up to this point to reflect @Value Subtracted's correction in comments.] The answer is presumably that they needed to reassure the Klingons that something like the Augment Virus would never happen again. Hence they instituted a blanket ban around that time -- perhaps in 2155, the year after the Klingon Augment Virus crisis and also, according to Michael Burnham, the year the Geneva Protocols on Biological Weapons were updated.
That bought the Federation over a century of peace, but after war broke out due to a paranoid faction of Klingons who thought humans would dilute Klingon purity and after peace was only secured through the most improbable means, they doubled down on the ban. Una's revelation provided a perfect opportunity to signal to the Klingons that they were serious about the ban -- hence why they would add the charges of sedition, perhaps. Ultimately, an infinitely long speech and the prospect of losing one of their best captains combined to make them find a loophole -- but not to invalidate the ban or call it into question. This Klingon context is why April, who we know is caught up in war planning of various kinds, is so passionate that the ban exists "to prevent genocide" -- he's not thinking of people like Una, he's thinking of the near-genocide they suffered at the hands of the Klingons.
This theory still doesn't paint the Federation in a positive light, since they have effectively invented a false propaganda story to defend a policy that has led to demonstrable harm. But it makes a little more sense, at least to me. What do you think?
The danger is in what gets defined as a "defect". I think we'd all be comfortable fixing congenital heart failure before birth, and I (hopefully) assume we'd all be very uncomfortable with "fixing autism". There's a big blurry area between those two things, and I think Trek has largely correctly tended on the conservative side.
But I like how this theory ties the timeline together in a way that makes a bit more sense, because the "risk of another Khan" is not, at this point, the most interesting problem with gene editing in Star Trek to me
I don't know that I fully agree. I think a lot of people who get upset about attempts to cure autism are people who are able to function in society independently, along with people who get upset on behalf of people with autism and/or are self diagnosed because they do things that fit the profile.
Contrast this with some people I know who have a now-adult child who is, to be clear, very intelligent, but he's nonverbal, will probably never drive, will probably have great difficulty holding down a job, all things that make life in current society difficult. Add the message of last night's SNW's episode in. Not everyone is an angelic, understanding soul. These folks I'm thinking of have had a lot of problems with prejudice. Add in that they're probably on board with having their child at home for life and having to worry about who takes over for them when they're not able to.
As far as I know I'm not on the spectrum even though honestly I should probably be checked. I do know about other, diagnosed problems that get in the way of what people would call "normal", and honestly if someone said I could get an mRNA injection to change that, I would. If they'd come to me 20 years ago and said, we can't cure you but we can make sure this ends with your generation, absolutely, no question.
I personally honestly think the line should be disease and disorders, full stop. Gattaca, in other words. I know we won't be able to stop rich people from ordering pretty and athletic kids eventually but the line should be drawn nonetheless.
If you want to make the argument that people should be able to modify themselves I 100% back that up. In fact I think that probably would have fixed my problems with this episode, if this is something more like a rite of passage that Ilyrian adolescents choose to undergo then the whole thing gets way less ethically messy because now you're letting people make decisions about themselves that are socially influenced instead of having decisions made for them that are socially enforced. But I have really strong aversions to society deciding what types of bodies and minds even get to be born.
From my limited understanding genetic issues are caused by something going wrong, so a scientist can tell you exactly what went wrong and what are the side effects. For example maybe at point X you should have some gene ABC but you had bad luck and you have ABBC and this will cause issues.
So IMO if your child has such an real defect that is 100% scientifically proven that is not normal but an accident that happens very rare then as a parent you should have the right to decide to fix it or decide to let the child to live with it and maybe cure it later if possible.
I do not think we know if Bashir had such a defect in the DNA or he just inherited some "bad" traits from both parents and he did not get a cure but enhancements.