As this thread becomes increasingly polarised (pax who can't bear the possibility of the proximity of children vs parents who can't bear to concede that the presence of children may sometimes be irritating), it strikes me that what we're missing is a bit of tolerance.
Has modern life become so stressful that, unless we can control our environment exactly/be surrounded by only by people who are exactly like us (fellow harrassed parents/stressed-out business travellers) - we feel deeply uncomfortable?
What about others who makes us uncomfortable or get in our way? The elderly or disabled passenger limping slowly down the aisle, while we're stuck behing them desperate for the loo/another drink? Do we segregate them as well?
I am as annoyed by the next person by the parent who lets their children run riot and make life unpleasant for those around them. But what about responsible parents, with well-behaved kids, trying desperately to shut the baby up?
How much would the atmosphere change in the cabin if, instead of being met with a scowl, harassed parent receives a sympathetic smile from stressed-out business person? And if harrassed business person receives a rueful smile and a muttered "I'm so sorry about this" in return?
It's a hackneyed fact that we were all children once, but also that we all different, with different needs. We can't/shouldn't (IMHO) isolate ourselves from the rest of the human race. How about a bit of empathy/understanding instead?