Why would we expect that genetic engineering would be any more difficult that genetic engineering that doesn’t involve conscious gene splicing? We already genetically engineer. We’ve been doing it with ourselves for probably hundreds of thousands of years. When you choose a mate because they are beautiful or strong, or whatever, you are genetically engineering.
What’s the difference when you know gene sequences, and can do your engineering a little bit more specifically? We’re not changing anything we’ve been doing at any fundamental level; we’re merely changing the precision with which we can do it.
So, since we already have plenty of genetic mutations that make it difficult for children to grow up or participate in society, and we already do our best for these children, I don’t see why it would be any different with a precisely engineered child? If they have a mutation, we’ll still love them. Or we shouldn’t be parents in the first place.
However, with more precise engineering, we will probably have fewer dangerous mutations than if we didn’t use these tools to engineer our kids. Now disabilities rights groups might complain about that, as they complain about separating out in vitro kids that have something ‘bad’ in their genes. Those embyros may not even get made, if we have good engineering.
Anyway, if it isn’t clear that I’d use genetic engineering by now, let me say that I wouldn’t have kids if it didn’t exist. The sperm and eggs for my kids were mixed deliberately by a lab technician. Not that they knew what they were putting together, but still, it required human intervetion. I have to say, they did a hell of a good job, too!