Replace dozens of kids with any piece of wanton consumption then. How is it checked? Hoping we get bored of orgies and parties and feasting and this is enough to ensure we can reproduce indefinitely and continue to orgy and party and feast? I don't think so. At the end of the day, the world cannot sustain everyone living with the carbon footprint of a wealthy person living life to excess. It can't even sustain the carbon footprint of everyone living how they currently live.