Some people say only to treat abnormalities. But why stop at normal? If what is average in our world for intelligence were the intelligence of only 1% of people in another world and in that other world everyone else had a higher intelligence then what we consider average in our world would be "abnormal."
Also what if genes code for "above average" in some respects and "below average" in others? Is it more disease or more gift?
Disease v. Not disease isn't as cut and dry as people think it is. As long as the technology is proven safe it should be approved. Some line-drawing will have to be drawn whenever there are genetic choices that come with tradeoff effects where no matter what there will be some positive and some negative, but if the negative isn't too bad or if the positive compensates for it well enough parents should be able to make that choice.
It won't be long after we can change genes in the womb and we'll be able to change genes for adults, so then if the child grows up and is unhappy with their genome they could get it changed again.
I have no problem with parents genetically manipulating their child in-vitro, in the womb, in the bright clear air of society. Children are not fully persons - understanding their selves in a world of other people - until they are 5 or 6 so parents should do what they can to give them the best position in our brave new world.
Is there moral outrage when parents correct their children's vision or take them to the doctor when they are sick? No. Is there anger when they are vaccinated against diseases at birth? A little, but not for logical reasons. Is there a compelling reason to deny parents treatment of their children in the womb?
I think parents should be able to genetically manipulate their child while in the womb only if testing revealed a genetic abnormality, or one of the parents was found to be a carrier for a genetic abnormality. I think genetic manipulation for these reasons would be very acceptable in order to give the child a better chance for a healthy, normal life.
I believe that it would be ethically wrong to change a child's genetic makeup just to cater to the aesthetic desires of its parents. This would also greatly increase the chances of a miscarriage, as the still-developing body of a child is still susceptible to changes in its developmental features. This should only be done in medical emergencies with a legitimate medical reason, such as a defect or tumor being discovered.
It is wrong for parents to tailor their children to fit their needs, the child is it's own person, and it should be loved whether it has brown or blond hair, blue or brown eyes. If everyone started modifying their children, it might also cause problems for the general development of the human race.
No, parents should not have the ability to alter their children's genetics while the child is still in the womb. While this could prove useful in disease prevention, in general is could be looked at as "playing God.." That is a risky thing to do, and if we allow it in some cases, it will be difficult to draw the boundaries between what would be acceptable or not.