I wasn't going to respond to this thread but I just can't help myself!
I think world population is a really interesting and valid debate and it's a shame it can't be had without attacking other peoples choices. As yet, there is no worldwide law or accepted number around the amount of children a couple can have so your opinions on it are really just that - your own personal views.
It's interesting someone earlier said that they consider 2 children to be the 'acceptable' number to have, based on the fact that they replace the parents and no more. Well my view (and it is just my own view) is that 3 children is the 'acceptable' number based on the fact that not everyone has children and that not all children survive into adulthood. Of course, in terms of a need to reduce the global population, someone else might consider that 2 or even 1 is irresponsible. It's just opinions - I actually have no idea, if some world wide limit were set, what the maximum number of children a couple would be allowed to have in order to maintain population and support our ecomony and industries and older generations, taking into account that not everyone has kids and some don't survive, natural disasters etc etc.
In terms of world population, much of the increase is down to an increased life expectancy. And many countries - Japan, Russia, Germany - have a declining population. The fact that parts of Asia and Africa and the world overall have growing populations does not really impact these countries potential social and economic issues that their declining population may lead to, so I think it is too simplistic to say that someone in Europe, where people tend to have smaller families, is wrong to choose a bigger family because of population growth elsewhere in the world.
In fact there are very different views on where we are headed in terms of world population and the potential impact of its growth and what the Earth can actually sustain. It is just not so simplistic and straightforward as to be able to say everyone should have 2 children and that will solve things.
I do think that environmental impact is a slightly different issue and I must admit that I do sometimes question my decision to have 3 children when it comes to this.
Anyway, sorry for the essay, I just think it's a very valid debate with many different views and it would be good to be able to discuss it openly.