According to a new study that identifies the most effective ways people can cut their carbon emissions, the greatest impact individuals can have in fighting climate change is to have one fewer child. That’s a sad conclusion as having children is arguably the most fulfilling dimension a human being can add to her or his life. So, it may be good news that an expert on demographic issues wrote an article challenging the assumptions of the study. “In the vast majority of cases, how many kids you have just won’t affect any environmental outcomes. Plus the study on which these articles were based is junk science.”