I think the point is that we don’t specify how many children people can have at all. In addition to being ethically dubious, it has a high chance of backfiring as it had in China, and likely will be ineffective, as most population growth is currently relatively localized to a few areas of the world like the Middle East and Africa. Places like the US or Europe or East Asia have already largely stabilized population wise. What remains to be done is making the emissions per person sustainable, which isn’t true especially in the West. This in turn will make the technologies required for reducing emissions cheaper and more widespread for those countries that are still growing to utilize before their emissions per capital grows to that of current rich nations. Population control is a non-starter.

Just wanted to be clear that I think everyone should have the number of children they want to have. I don't think the government should interfere in that decision and it should be up to the couple whether they have lots of children, one or two, or none. Just wanted to point out an interesting point about efficiency of some families as a response to the parent. And I'm not even definitively saying that I'm right, but it is a perspective.

I think even families with only a few children _can_ be more efficient, but it is not the natural thing to do, and people with fewer children often do so because they prioritize higher resource consumption from a perception of quality of life or other factors.

I guess the main point is that these things aren't clear cut, there are reasons for both depending on a person's perception of life and pursuit of happiness. That's the tricky thing, even when we believe a problem is simple from out perspective, it usually isn't.

It is funny, how one gets downvoted for asking someone to elaborate their point on HN.