The items you mention are intellectually interesting, but somewhat counterintuitively, do not influence population growth in the way that one might expect. Case in point: breakthroughs in medicine and agriculture.

One might expect that access to food and medicine leads to population growth, but in the long term, countries with the highest levels of access have the lowest population growth. It's quite a strange phenomenon, and it is basically this trend which leads statisticians to estimate 2070 as having a peak population.

"It's quite a strange phenomenon, and it is basically this trend which leads statisticians to estimate 2070 as having a peak population."

Yes, but it might be a missleading one. Because I think our society causes many people to consider children as expensive and time-consuming and therefore not wanting to have children.

But that might change again. There were times when childrens were be seen as a luxery or as a necessity, a insurance for old age.

I mean, I am not saying it will change to that or that direction, but I think you can't really predict the future on how the world is acting today as human society changed quite drastic in the last hundreds years. I would rather predict that human society will continue to change and therefore I am very cautious with any fixed predictions.

Children are expensive and time-consuming, because in our society we're expected to take care of them, and the standard for that is very high. In developing countries, the standard is much lower and children are able to help run the household, so they're incentivized to have more children. As the things that make a country 'developed' spread in developing countries, the equation starts to tip the other way...

This is definitely the line of rationalisation I'd use to explain the trend. The person replying to me wasn't entirely wrong in questioning whether it would continue, however.

E.g. I can certainly envision post-work economies, where the "penalty" of having multiple children is much lower, as they are essentially guaranteed a good life. I wonder which direction society's value system would evolve in that scenario.

The answer to solving world hunger is not necessarily reducing human population. Are you sure it is me who is cynical here?

Additionally, more humans are expected to die from obesity than from hunger, as of now.

"The answer to solving world hunger is not necessarily reducing human population"

I did not say that. I just said that the problem is clearly not solved, when so many people are starving.