I do think the world is overpopulated. We are squeezing out other species. Animals have nowhere to go. It's very obvious the entire world cannot live in a four-bedroom, three-bath home that's kept heted or cooled 24/7 and contained 1-3 people who eat meat twice a day, etc. However, even if we all became vegetarians living in huts, we still would do the world a favor if many of us had no children (which works out fine since lots of people don't want them) and if most of the rest of us hold ourselves to one or two, ideally.