Should people be able to choose their baby's sex, skin colour, intelligence, etc.? I propose a guideline that has the following foundation: the limitations of direct genetic engineering on babies should be the same as those of indirect selection through choosing who to have the baby with.
Guidelines are important here because there is a fine line between the inalienable human right to reproduce by choice with whomever, and outright eugenics (creating a human "superior master" race).
I don't believe eugenics would be the main issue. After all, how many people would choose to have a child not genetically theirs because they objectively assess themselves as ugly and stupid (chuckle)?
I believe the main issue would be an amplification of the already existing set of expectations parents lay on their children before they are born.
A baby's general appearance can be selected indirectly by mate selection, therefore to that extent it should be available in genetic engineering. Thankfully, our genome is not as discerning as we are, and most features are not monogenic.
You could select your baby's rough height, skin/hair colour, rough facial features, but you could not select the precise nose-mouth size ratio. Eye colour itself is a combo of around 16 genes.
You can't select your baby's sex by choosing different partners - and so you shouldn't have that option through genetic engineering (again, not because there's something wrong or dangerous with that; there isn't; but because it would inflate parent expectations in a harmful way).
Many attractive features such as sense of humour, occupation, and appearance are not inheritable e.g. make up, exercise, so in fact any genetic engineering should be focused on optimising health; any remaining subjective features should be put through the "if I chose a partner" test.
If a feature could not be chosen indirectly through the partner, it should not be available directly via genetic engineering.