Population growth isn’t due to people having more babies. It’s less babies dying and people living a whole lot longer, combined with contraceptive education that’s been going on for about forty years in the poor and poorest of nations, resulting in an extreme reduction in the number of birth per family on average.
But since people are living longer, there’s more time for more couples to be born to more families. They’re smaller families but more families (that are smaller – average 2.2 kids per family rather than averageof 6-9 40 years ago in impoverished countries).
There’s better industry, better technology in those places and yet apparently American and British education (including in our textbooks) is 40 years behind the times in this information generally so a lot of old myths persist.