Actually I don't think the issue here in Australia and many other western countries is families having 2 or more children per se.
More, it is that their families dont have a minimum 2 cars, 3 bathrooms, fully ducted airconditioning, a swimming pool, two large flat screens and three computers, food to waste every week, clothes that get worn for a season, annual or at least regular holidays involving flights half way around the world.
It needn't be depressing, it just needs to be viewed differently.