Population can not grow indefinitely within the finite constraints of a nation's borders. Similarly, population can not grow indefinitely within the finite constraints of planetary land mass.
I find the study of Human BioDiversity (HBD) fascinating. I think it ultimately explains a lot of the differences between ethnic groups and nationalities, especially regarding fertility, altruism, and the construction of complex societies like Western Civilization.
"If you're ... pathetically weak, the country is going to be overrun with millions of people, and if you're strong, then you don't have any heart, that's a tough dilemma. ... I'd rather be strong."
Most recently, in the Data is Beautiful subreddit, the trend has been to use data visualization techniques to split up the maps of countries into four evenly populated areas.
The preliminary birth figures for 2017 are in. The following graph and table show the percentages of births by state that were to non-Hispanic white babies: