Conditional on the child's existence, it's better for them to be healthy than neutral, but you can't condition on that if you're trying to decide whether to create them.
If our options are "sick child", "neutral child", and "do nothing", it's reasonable to say that creating the neutral child and doing nothing are morally equal for the purposes of this comparison; but if we also have the option "healthy child", then in that comparison we might treat doing nothing as equal to creating the healthy child. That might sound inconsistent, but the actual rule here is that doing nothing is equal to the best positive-or-neutral child creation option (whatever that might be), and better than any negative one.
For an example of other choices that work kind of like this - imagine you have two options: play Civilization and lose, or go to a moderately interesting museum. It's hard to say that one of these options is better than the other, so you might as well treat them as equal. But now suppose that you also have the option of playing Civ and winning. That's presumably more fun than losing, but it's still not clearly better than the museum, so now "play Civ and win" and "museum" are equal, while "play Civ and lose" is eliminated as an inferior choice.
Conditional on the child's existence, it's better for them to be healthy than neutral, but you can't condition on that if you're trying to decide whether to create them.
If our options are "sick child", "neutral child", and "do nothing", it's reasonable to say that creating the neutral child and doing nothing are morally equal for the purposes of this comparison; but if we also have the option "healthy child", then in that comparison we might treat doing nothing as equal to creating the healthy child. That might sound inconsistent, but the actual rule here is that doing nothing is equal to the best positive-or-neutral child creation option (whatever that might be), and better than any negative one.
For an example of other choices that work kind of like this - imagine you have two options: play Civilization and lose, or go to a moderately interesting museum. It's hard to say that one of these options is better than the other, so you might as well treat them as equal. But now suppose that you also have the option of playing Civ and winning. That's presumably more fun than losing, but it's still not clearly better than the museum, so now "play Civ and win" and "museum" are equal, while "play Civ and lose" is eliminated as an inferior choice.