If there were no intrinsic reasons for giving moral consideration to babies, then a society in which some babies were (factory-)farmed would be totally fine as long as the people are okay with it.

If there were no intrinsic reasons for a feather to fall slower than a rock, then in a vacuum a feather would fall just as fast as a rock as long as there's no air. But you don't neglect the viscosity of air when designing a parachute.