A blanket ban condemns families to watch kids suffer from Huntington's or Tay-Sachs when we could prevent it. Allow it for serious disease, draw a hard line at enhancement.
Allow it only to stop serious genetic disease. Banning it traps families in preventable suffering, while enhancement opens the door to designer-baby abuse.
If we can literally erase diseases like cystic fibrosis from a family line forever, we have a moral duty to do it. A total ban just guarantees future generations suffer needlessly.
Banning it outright dooms families to preventable diseases like Tay-Sachs. Restrict strictly to curing serious conditions and we fix suffering without playing god.
