Sure, but there are a lot of grey areas. Would you want your loved ones removed from the gene pool because they have peanut allergies, or what about asthma from living near a coal plant? What if some governing body determined that you're unfit for reproduction because of your height or facial structure?

Moreover, genes are not binary in the sense that there are "good" or "bad" traits. It depends on the time and place like sickle cell anemia, which gives you immunity to malaria, but has the obvious downside of making you anemic.

And there are those naturally immune to diseases like smallpox or even AIDS [0], even diseases we have no knowledge of right now.

I once had a fellow coworker who hinted at the fact that he was pro-eugenics (semi-jokingly) as he was a varsity athlete from a good college in good health. I had to remind him that just a bit over 100 years ago the US signed the Chinese Exclusion Act and that Hitler would not have considered him to be anything close to a true Aryan.

[0] https://en.wikipedia.org/wiki/Innate_resistance_to_HIV

The problem is that there's not always a clear consensus on what is considered an "improvement." Back then (as well as today in many non Western societies), for example, homosexuality was considered a genetic flaw that was targeted for elimination in the gene pool.

So one person's improvement might be another's worsening. And we've seen our opinions evolve over time.

As a consequence there's a serious ethical concern. As flawed human beings I don't think any of us can say with certainty how we should manipulate the gene pool. Allowing Nature to do it herself has worked reasonably well thus far, if you consider the evolution of Homo Sapiens to be a positive outcome.

> homosexuality was considered a genetic flaw that was targeted for elimination in the gene pool.

I don't wish to come across as callous, but wouldn't homosexuality self-eliminate itself from the gene pool nowadays because there is no societal pressure anymore on homosexuals to maintain appearance of heterosexual couples?

If I understand correctly homosexuality is (relatively?) common in other species as well, and I would be surprised if there's societal pressure there.

Of course, if I'm correct in my assumptions, it's fascinating why homosexuality exists.

By that logic, Lasik is ethically dangerous because some people have regarded brown eyes as inferior in the past.

That slope isn't anywhere near as slippery as you're trying to make it out to be.

So much suffering is caused by genes, from physical to mental illnesses. It's hard to imagine what would be wrong with a world where no one got cancer, became schizophrenic, or perhaps, even suffered from depression. The big danger I guess is that we end up deciding there is only one (or perhaps a couple) valid human "types", and eccentric perspectives that create value (in any sense) are lost, not through extermination, but because they just are never created to begin with.

The gradual improvement of the gene pool will likely happen anyway, as parents choose to use new technologies to improve their future children in various ways.

Well, Tay-Sachs is also prevented through similar measures sometimes.

https://en.wikipedia.org/wiki/Prevention_of_Tay%E2%80%93Sach...