It's flawed accounting. If my carbon footprint is doubled because I have a child, then my child's carbon footprint is zero; it's already been counted into mine. Maybe my father's footprint is doubled because he insinuated me into the world...then I don't count as destroying the earth. And if it's x5.7, then it's 2.85 times as stupid. Treehuggers love making up tricky bogus facts like this.