This is not an experiment on a ‘kid’. The kid doesn’t exist until the end of the process, and it has already given children a chance at a healthy life.
And sometimes people might not know for sure if their child will or will not be born with a genetic disease. They only know there’s a chance.
In the future, genetic engineering is predicted to treat cancer, cystic fibrosis, multiple dystrophy and a host of other diseases. It will be a long time before we can truly know the long term effects if any; but I doubt many people suffering from those will refuse treatment for themselves or their children.
Know for sure?
If they're going in and modifying DNA, they're betting the child would have been born with a genetic disease.
If you're betting against your own DNA, or your spouse's DNA, don't have kids and gamble with their life nor their offspring's either.
Predicted.
I still don't have my jet pack.