I mean this is 1/2 pedantry 1/2 not, I'm sure there is a situation that almost anyone in existance would agree a person shouldn't have kids, but that doesn't make it a fact that they shouldn't have kids. Almost anyone would agree having a kid in a family that is constantly screaming and toxic that leaves the child a depressed anxious adult is immoral. That's about as close to "objective" as you can get with morality, even if it is still subjective.