I can't tell you how many time I've had the conversation with well-intentioned, environmentalist "progressive" folks about this one little (huge) bit of "common sense" wisdom. I've heard "Well we all know that the earth is overpopulated" and seen people who sneer "!@#$ breeder" when they see a poor woman with a couple of kids.
The planet isn't overpopulated. There is a resource distribution problem, with the vast majority of resources going to the wealthy global north, and if the poor used resources at the rate the non-poor do, then yeah we'd be in a fuck of a lot of trouble. Thankfully, Sociological Images has a guest post about the exact same perception problem. In the future I may just tattoo the link on my arm so I don't have to type this again.
Us poor folks, either domestically or internationally, have a fraction of the resource foot print that non-poor people do. We own fewer (or no) cars and walk or use public transit. We own fewer electronics and are more likely to get them second hand. We own fewer articles of clothing, eat less meat, etc etc etc all because these things are fucking expensive and every penny counts.
Now this doesn't mean I don't full-throatily support programs that give poor women (domestically and internationally) more control over their own reproduction and family size. Everyone should be able to choose if, when and how many children they want responsibility for. But I don't support reproductive freedom as some backhanded form of eugenics because I'm scared of a brown menace. And that is what arguments about overpopulation often sound and look like.