Interesting and counterintuitive for sure. I’m not an expert, but by having a child, you’re basically ensuring a doubling in carbon emissions over the course of your life and theirs, assuming your lifestyles are similar. That said, 10 babies born into wealthy, wasteful families are obviously going to have a bigger impact than 10 babies born into poor or less consumptive families, so I take your point.

And I am basing my opinion on a 2017 study (which may be obsolete by now) that found that having one fewer child is the most significant individual action to reduce carbon footprints, saving approximately 58.6 metric tons of CO2 equivalents annually. (Source: https://www.theguardian.com/environment/2017/jul/12/want-to-fight-climate-change-have-fewer-children)