There are some good arguments for not having kids or for having as few as possible. Environmentally, having no kids COULD lead to a smaller ecological footprint, but that obviously depends on what you do with your childfree life.  There is also a good point to be made that there are lots of kids who need families out there and that it's better to take care of them than to make new kids.

 The idea that it's cruel to have children because we're inflicting suffering upon them doesn't quite add up for me, though.  My child will feel both joy and sorrow in her life time; it's up to me to help her to choose joy and deal with sorrow.  While there is no doubt that life is full of suffering, it's also full of hope, love, playfulness, work, challenges, wonder, etc.  Besides, each child could make the world a better place.  I know it's cheesy, but remember It's a Wonderful Life?  Everything would have been worse if George Bailey hadn't been born.

A good point but what about thsoe who will never know joy? Those who have little to no food/drinking water? Those who are surounded by violence and starvation? Would things not be better for them if they had never been born? (I know that sounds almost racist but it's not meant to be, it's just a thought). If you're not born then you will not know suffering. In a way, to have a child is to force suffering upon them. For us that suffering is balanced by joy and happiness but for many it is not and so to bring life into the world can be seen as bringing pain and saddness into the world.