It for certain isn't smart to try to aim to make a child's life utterly without bumps but I'd argue in some cases where the family itself is already suffering from major issues a child certainly isn't likely to be a grand idea. It's still the choice of the pair/person though and they're allowed to do what they wish, but I've met far too many who mistakenly believe a child can help their situation (especially with relationship bumps). It very, very rarely pans out that way and the child ends up with a lot of major issues down the road because of the turmoil they're brought in to.
Still in the end I doubt that is really what most childfree people are even thinking on. I'd not consider 'Being short' suffering, I'd consider that.. just a potential part of who they are as a person. I've seen loads of people (usually men) who think being short is some sort've life long curse though, perhaps that's a good part of it.