Designer baby concept.

Well that slippery slope is a long ways off. There are not genes that directly determine those traits, as there are with certain diseases. Now I agree that "designer babies" is a complex issue and there is an enormous amount of room for abuse, but this was not a designer baby. Just selecting the most healthy egg a mother has is fine by me.

There's a huge difference between parents choosing the traits they want their baby to have and the government making that choice for them. Hence, I see nothing at all wrong with parents trying to make their child prettier, smarter, stronger, etc. Trying to make a child more willing to trust a leader is not a choice that parents are likely to make.

This specific case is unambiguously moral, though. We should do everything we can to make sure that children are not going to be born with diseases. Anything we do that makes that less likely is moral. Slippery slope arguments are inherently flawed because they use extreme possibilities to try to show that the normal cases are bad. That's just not a sound argument. What these parents have done is right regardless of what else this technology can be used for.

In my opinion there's nothing wrong with picking the healthiest eggs in order to remove genetic deseeces like cancer, even if it involves genetic manipulation. However, this has nothing to do with just that. As pointed out above, it's simply a matter of picking the best egg.