How would you like to be born a mistake in such experimentation. That's why the ethical issues are serious. If it's not safe, the mistakes will be paid for by utterly innocent and unwilling participants.
How would you like to be born with Huntington's disease, knowing that your parents could have taken an unknown risk to save you from it?
We are all utterly innocent and unwilling participants in being born. You can either take the random cards that nature deals you, or we can try to act to have better outcomes. Just because you refuse to take action doesn't absolve you from taking a suboptimal action.
This could also easily turn into a larger discussion about the ethical considerations of procreation when one is not in a favorable position (e.g. poor, homeless, addicted to drugs, mentally ill). What's OK and what's not? Who decides for everyone? Is that the best way? Should people be allowed to decide for their future children?
That larger topic is indeed a touchy one. I tend to have a controversial stance in that discussion, so I do get plenty of down votes on it. Somehow, people feel very strongly about about adults' "rights" to procreate. Even if that right results in the involvement of an unwitting participant who then leads a very short life of struggling.
It's actually very saddening to watch a completely avoidable & preventable problem, whose N-amount of obvious solutions end up being shoved under the rug because we refuse to draw the line.
the end goal in this is a class of priest-like experts to decide, obviously. I'm surprised no one realizes the tyranny of being forced to justify your right to procreate at all, let alone unguided by scientific experts with their own clear ideals of what should be done with your child.
Very few people are honest with themselves and admit the end goal is not making better, its making more controllable/more in aim with how the rulers want their population to be.