He was probably thinking of pension. Pensions do function in a same way ponzi scheme does, it relies on a new generation to bring in enough to pay out for the previous generation.
The problem in this is that when the population keeps getting older (less babies born), the younger gens need to pay more and more to keep up with the older gen. So basically if you decided to have only a 1 child instead of 4, you’d technically make it harder for your kid to provide pension payouts for you. This is why people argue against it.
I personally think pensions (along with most gov welfare) should just be replaced with UBI to vastly simplify the processes at very least, even if it still has the same problem with aging population