Some interesting comments. As a very frequent flyer (luckily mostly short haul these days) I have come across my share of children on flights. I have no problem with the quiet, well behaved ones... I probably did not notice them. But boy have there been some horrors. In Economy, the kid who sat behind me kicking the back of my seat for the whole flight while his parent/nanny did nothing. (Travelling from Hong Kong, a nanny or helper is just as likely as a parent!). Many times parents whose babies screamed for hours on end.. one of these was in J (a seat I paid for, not my company)... this baby just cried all night. For those of you who say "ear plugs or noise cancelling headphones"... seriously? Have you ever actually TRIED to block out the noise of a screaming baby using earplugs or noise cancelling headphones? I have, they have almost no effect at all. I was pretty upset about that. It does make a difference when you pay 10's of thousands of dollars for something out of your own money and some inconsiderate person brings their kid on board and disrupts sleep for everyone.
So - on balance, I'm in the category of ban babies and small children from J and F. Ideally, I'd ban them from all flights; or for the airlines to have special "kid-free" flights for those who are prepared to pay extra for some peace and quiet. And/or some special "kids" flights where there is some extra area for kids to play with each other while parents sit/eat and people like me who don't like them can avoid them! I don't think the airlines do enough to solve this problem and with a bit of imagination could probably make travel easier for both parents and other people.
My other beef is that parents seem to assume that everyone else loves their children - which is just not true! I was in the front row of economy on a flight (luckily a short one) near the bassinet and the mother of this kid asked me to hold it for a while. I'm not a parent - out of choice - and I really think that asking stranger sitting next to you to hold your kid is unacceptable. The post by the lady who enjoyed pampering the baby on her flight was touching... but please recognise that not all women are maternal and some of us have no interest AT ALL in playing with other people's kids!
And I liked the post by the person who pointed out that having children is a choice and may result in you having to change your behaviour. My parents went on holiday every year, but left my sister and I behind until we were about 10 and old enough to behave on flights, in restaurants and hotels etc. It was their belief that overseas holidays were something adults did as an escape from their domestic duties for a week or two an would not have inflicted their children on any class of flight! Mind you, that was 40+ years ago when attitudes were different and taking more care about others feelings seemed more important. I think we lost something along the way.